p0455 test hx: evaporative emission (evap) monitor & system · 2018. 10. 14. · ensure all...

P0455

TEST HX: EVAPORATIVE EMISSION (EVAP) MONITOR & SYSTEM

Question: Step 79

Question: misplaced diagram

NOTE: After each service or repair procedure has been

completed, reconnect all components. Clear DTCs. If any

EVAP components were replaced, perform VEHICLE

PREPARATION FOR OBD-II OR MONITOR REPAIR

VERIFICATION DRIVE CYCLE and EVAP RUNNING LOSS

SYSTEM REPAIR VERIFICATION DRIVE CYCLE. See DRIVE

CYCLES under ADDITIONAL SYSTEM FUNCTIONS. After

drive cycle is complete, repeat QUICK TEST procedures to

ensure all EEC-V systems are working properly and DTCs

are no longer present.

Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This

test is used to diagnose the following:

• Leaks in fuel tank, filler cap or vapor hoses.

• Faulty Canister Vent (CV) solenoid.

• Faulty Fuel Tank Pressure (FTP) sensor.

• Faulty carbon canister.

• Wiring harness circuits (CV, FLI, FTP, EVAP CANISTER PURGE, SIG RTN, PWR GND,

VPWR and VREF).

• Faulty PCM.

To identify EVAP system components, see appropriate illustration. See Fig 1-Fig 7 .

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1999 Ford Pickup 6.8L Eng VIN S F350 Super Duty

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Fig 1: Identifying EVAP System Components (Continental, Mustang, Sable & Taurus)

Courtesy of FORD MOTOR CO.



Fig 2: Identifying EVAP System Components (Crown Victoria, Grand Marquis & Town Car)




Fig 3: Identifying EVAP System Components (Econoline, Expedition, Navigator, Pickup & Ranger;

Also Used On Early Model Introduction On Contour, Cougar, Escort ZX2 & Mystique)


NOTE: Contour and Mystique use a 3-turn fuel filler

cap. All other models use 1/8-turn fuel filler cap.



Fig 4: Identifying EVAP System Components (Escort & Tracer; Also Used On Late Model

Introduction On Contour, Cougar, Escort ZX2 & Mystique)




Fig 5: Identifying EVAP System Components (Explorer & Mountaineer)




Fig 6: Identifying EVAP System Components (Taurus Flex Fuel & Taurus SHO)




Fig 7: Identifying EVAP System Components (Windstar)


NOTE: Check for presence of fuel cap. Go to step

2) before tightening a loose cap or checking for a

cross threaded cap.

1) Continuous Memory DTC P0442 This DTC indicates a fuel vapor leak has been

detected. Verify Canister Vent (CV) solenoid is properly seated on EVAP canister (if

possible). Visually inspect for cut or loose connector to fuel vapor hoses/tubes in

following locations:

EVAP canister-to-EVAP canister purge valve.

EVAP canister-to-fuel vapor vent valve assembly.

Fuel valve control valve tube assembly-to-fuel tank (if applicable).

Check for fuel filler pipe damage.

If no faults are found, go to next step. If any faults are found, repair as necessary. After

repair is complete, go to next step.



NOTE: When checking EVAP system for leaks or

blockage, energize (close) Canister Vent (CV) solenoid

for a maximum of 9 minutes per test step. Then de-

energize CV solenoid prior to performing the next test

step. This is done to ensure proper closing of CV

solenoid.

2) Check For EVAP System Leaks At Evaporative Emission Test Port Disconnect and

plug EVAP return tube (EVAP canister purge valve-to-intake manifold) at intake

manifold vacuum source. Turn ignition on. Using scan tool, select VPWR PID from

PID/DATA monitor menu. If PID voltage is less than 12 volts, go to step 61). If PID

voltage is 12 volts or more, locate evaporative test port (marked EVAPORATIVE

SERVICE PORT) between EVAP canister purge valve and EVAP canister. If vehicle

does not have a test port, go to next step. Install EVAP System Leak Tester (134-

00056) including compressed gas source (nitrogen or argon) and pressure regulator to

test port. Using scan tool, energize (close) CV solenoid by entering OUTPUT TEST

MODE, and turning all outputs on. Select ALL OFF mode and press START button on

scan tool. Regulate gas pressure on tester to 14 in. H O. Using instructions provided

with EVAP system leak tester, pressurize EVAP system. Follow system leak test

instructions provided with tester. If pressure stays at more than 8 in. H O, disconnect

tester and go to next step. If pressure drops to 8 in. H O or less, check fuel filler cap for

damage. Replace cap as necessary and retest. If fuel filler cap is okay, disconnect

tester and go to next step.

3) Check For Small Leaks At Fuel Filler Cap

Install EVAP system leak tester to fuel filler pipe. Turn ignition on. Using scan tool,

access OUTPUT TEST MODE. Turn all outputs on. Pressurize EVAP system to 14 in.

H O. Using leak detector provided with test kit, check for leakage at fuel filler cap area

and evaporative test port. If no leak is indicated, unable to duplicate fault at this time. If a

leak is indicated, replace fuel filler cap or evaporative test port (test port may be part of

EVAP canister purge valve) and repeat this step to verify repair. If leak is still indicated,

go to next step. If no leak is indicated, testing is complete.

4) Leak Test System With Tester At Fill Position

Connect EVAP system leak tester to evaporative test port. Turn ignition on. Using scan

tool, access OUTPUT TEST MODE. Turn all outputs on. Select ALL OFF mode and

push START button. Regulate gas pressure on tester to 14 in. H O. Follow system leak

test instructions provided with tester. Turn selector on tester to FILL position. Pressurize

EVAP system to 14 in. H O. If pressure stays at 13.8-14.2 in. H O, go to next step. If

pressure drops to less than 13.8 in. H O, discontinue pressurizing EVAP system and go

to step 6).

NOTE: To ensure CV solenoid remains closed, DO

NOT energize solenoid with scan tool for more than 9

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minutes. If necessary, de-energize CV solenoid with

some time passing then re-energize solenoid.

5) Check Complete EVAP System Turn ignition on. Using scan tool, access OUTPUT

TEST MODE. Turn all outputs on. Pressurize EVAP system to 14 in. H O. Using leak

detector provided with test kit, check for leakage between the following EVAP system

locations:

Check EVAP return tube-to-EVAP canister purge valve.

Check EVAP canister purge valve-to-EVAP CV solenoid.

Check EVAP canister-to-fuel tank.

Check fuel filler pipe and fuel cap.

If leak is detected, repair as necessary. After repair is complete, go to next step. If no

leak is detected, discontinue pressurizing EVAP system and go to next step.

NOTE: Mustang, Ranger, Town Car and Windstar

have a quick disconnect between the EVAP canister

tube and front fuel vapor hose assembly (fuel tank-to-

EVAP canister). This quick disconnect is used as an

alternative location to a fuel vapor tee or "F" fitting on

the EVAP canister for leak check purposes.

6) Check For Leak Between EVAP Return Tube & EVAP Canister Turn ignition off.

Disconnect EVAP canister tube (from fuel tank) at fuel vapor tee located between EVAP

canister purge valve and EVAP canister (or "F" fitting on EVAP canister). Plug or cap

fuel vapor tee (or fitting on canister). Turn ignition on. Using scan tool, access OUTPUT


detector provided with test kit, check for leakage at the following EVAP system

locations:

Check EVAP return tube (intake manifold-to-EVAP canister purge valve).

Check EVAP canister purge outlet tube (EVAP canister purge valve-to-EVAP

canister CV solenoid assembly.

Check EVAP canister vent hose.

If no leak is indicated, remove plug or cap from fuel vapor tee (or fitting on canister). Go

to next step. If a leak is indicated, repair as necessary and repeat this step to verify

repair. Go to next step.

7) Check For Leak Between EVAP Canister Tube & Fuel Tank

Turn ignition off. Remove EVAP system leak tester. Remove fuel filler cap. Install EVAP

system leak tester to fuel filler pipe. Plug open end of EVAP canister tube (from fuel

tank) at fuel vapor tee (or fitting on canister). Turn ignition on. Turn selector on tester to

FILL position. Pressurize EVAP system to 14 in. H O. Using leak detector provided with

test kit, check for leakage at EVAP canister tube between fuel tank and EVAP canister.

Also check for leakage at fuel tank pressure sensor, fuel vapor vent valve(s) fuel vapor

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control valve and fuel filler pipe. If no leak is indicated, go to next step. If a leak is

indicated, repair as necessary. Repeat this step to verify repair then go to next step.

8) Verification Leak Check At Fuel Filler Pipe

Turn ignition off. Reconnect EVAP canister tube to fuel vapor tee (or fitting on canister)

Turn ignition on. Using scan tool, access OUTPUT TEST MODE. Turn all outputs on.

Pressurize EVAP system to 14 in. H O. Follow instructions provided with EVAP system

leak tester and perform system leak test. If no leak is indicated, no fault is indicated at

this time. Testing is complete. If a leak is indicated, return to step 4). Repair as

necessary and repeat this step to verify repair.

NOTE: A break in step numbering sequence

occurs at this point. Procedure skips from step 8) to

step 10). No test procedures have been omitted.

10) Continuous Memory DTC P0443

This DTC indicates an intermittent EVAP canister purge valve circuit fault. Repeat

KOEO ON-DEMAND SELF-TEST and KOER ON-DEMAND SELF-TEST. If DTC P0443

is present in Continuous Memory only, check for intermittent fault. Go to TEST Z . If no

fault is indicated after performing TEST Z, replace PCM. If DTC P0443 is present in

KOEO or KOER self-test, go to next step.

11) DTC P0443: Check VPWR Circuit Voltage

Turn ignition off. Disconnect EVAP canister purge valve connector. Turn ignition on.

Measure voltage between VPWR terminal at EVAP canister purge valve wiring harness

connector and negative battery terminal. See Fig 8. If voltage is more than 10.5 volts, go

to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit.

Fig 8: Identifying EVAP Canister Purge Valve Circuits & Connector Terminals


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12) Check EVAP Canister Purge Valve Resistance

To check EVAP CANP valve resistance, engine must be cold. Turn ignition off. Measure

resistance between EVAP canister purge valve terminals. If resistance is 30-38 ohms,

go to next step. If resistance is not 30-38 ohms, replace EVAP canister purge valve.

13) Check EVAP Canister Purge Valve Circuit Resistance

Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded

terminals. Measure resistance between PCM connector pin No. 56 and EVAP

CANISTER PURGE terminal at EVAP canister purge valve wiring harness connector. If

resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair

open in EVAP CANISTER PURGE circuit.

14) Check For Short To Ground

Disconnect scan tool from DLC. Measure resistance between PCM connector pin No.

56 and negative battery terminal. If resistance is 10,000 ohms or less, repair short to

ground in EVAP CANISTER PURGE circuit. If resistance is more than 10,000 ohms, go

to next step.

15) Check Circuit For Short To VPWR

Turn ignition on. Measure voltage between PCM connector pin No. 56 and negative

battery terminal. If any voltage reading is more than 10.5 volts, repair short to VPWR in

EVAP CANP PURGE circuit. If both voltage readings are 10.5 volts or less, replace

PCM.





This DTC indicates that PCM has detected EVAP control system has excessive fuel

tank vacuum. Possible causes are:

EVAP canister purge tube blocked or kinked.

Fuel vapor elbow on EVAP canister is contaminated.

Restricted EVAP canister.

Canister Vent (CV) solenoid stuck closed.

Plugged or contaminated CV solenoid filter.

EVAP canister purge valve stuck open.

Fuel filler cap stuck closed (no vacuum relief).

Open in VREF circuit.

Faulty Fuel Tank Pressure (FTP) sensor.

Check for kinks in fuel vapor hoses/tubes. Visually inspect EVAP canister inlet port, CV

solenoid filter and canister vent hose for contamination or debris. Check CV solenoid

filter for blockage or contamination. Repair as necessary and go to next step. If no faults

are found, go to next step.

19) Check For Blockage

Disconnect and plug EVAP return tube (EVAP canister purge valve-to-intake manifold)

at intake manifold vacuum source. Plug CV solenoid (or filter) or plug canister vent



hose. Locate evaporative test port (marked EVAPORATIVE SERVICE PORT) between

EVAP canister purge valve and EVAP canister. Install EVAP System Leak Tester (134-

00056) including compressed gas source (nitrogen or argon) and pressure regulator to

test port. Regulate gas pressure on tester to 14 in. H O. Using instructions provided

with EVAP system leak tester, pressurize EVAP system. Remove plug from CV solenoid

(or filter) or from canister vent hose. If pressure drops rapidly, remove EVAP system

leak tester and go to next step. If pressure does not drop rapidly, blockage exists. Check

the following:

Check for faulty vent solenoid.

Check for faulty or plugged EVAP canister.

Check for kinked, plugged or damaged EVAP hoses/tubes.

Repair as necessary and repeat this step to verify repair. Go to step 22).






solenoid.

20) Pressure Check Fuel Filler Cap Install EVAP system leak tester to fuel filler pipe.


Pressurize EVAP system to 14 in. H O. Using leak detector provided with test kit, check

for leakage at fuel filler cap area and evaporative test port. If no leak is indicated, go to

next step. If a leak is indicated, replace fuel filler cap or evaporative test port (test port

may be part of EVAP canister purge valve) and repeat this step to verify repair. Go to

next step.

21) Check For Blockage With Fuel Filler Cap Removed


Pressurize EVAP system to 14 in. H O. Remove fuel filler cap. If pressure drops rapidly,

remove EVAP system leak tester and go to next step. If pressure does not drop rapidly,

blockage exists. Check the following:




Repair as necessary and repeat this step to verify repair then go to next step.

22) Check Fuel Tank Pressure Sensor Parameter Identification (PID)

Remove fuel filler cap. Turn ignition on. Using scan tool, select FTP V PID. If PID

voltage is 2.4-2.8 volts, install fuel filler cap and go to next step. If PID voltage is not

2.4-2.8 volts, go to step 24).

23) Check For Stuck Open EVAP Canister Purge Valve

Turn ignition off. Remove plug from CV solenoid (or filter) or from plug canister vent

hose (if not done previously). Remove plug and reconnect EVAP return tube (EVAP

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canister purge valve-to-intake manifold) at intake manifold vacuum source. Ensure fuel

filler cap is installed. Turn ignition on. Using scan tool, select FTP V and EVAPPDC

PIDs. Start engine. When EVAPPDC PID reading is zero, if FTP V PID voltage is less

than 2.4 volts, EVAP canister purge valve is stuck open. Replace EVAP canister purge

valve. When EVAPPDC PID reading is zero, if FTP V PID voltage is 2.4 volts or more,

blockage still exists in EVAP system between evaporative test port and fuel tank or

between EVAP canister and CV solenoid. Repair as necessary or return to step 19) to

help determine blockage location.

24) Check Voltage Between VREF & SIG RTN Circuits

Turn ignition off. Disconnect FTP sensor connector, located on top of fuel tank. Turn

ignition on. Measure voltage between VREF and SIG RTN terminals at FTP sensor

wiring harness connector. See Fig 9. If voltage is 4-6 volts, replace FTP sensor. If

voltage is not 4-6 volts, go to next step.

Fig 9: Identifying FTP Sensor Circuits & Connector Terminals


25) Check For Open VREF Circuit

Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose,

damaged or corroded terminals. Measure resistance between PCM connector pin No.

90 and VREF terminal at FTP sensor wiring harness connector. If resistance is less than

5 ohms, replace PCM. Go to step 22) to verify repair. If resistance is 5 ohms or more,

repair open in VREF circuit. Go to step 22) to verify repair.

26) DTC P0452: Check FTP Sensor Connector

This DTC indicates FTP circuit input is below minimum. Turn ignition off. Visually inspect

FTP sensor connector for liquid fuel contamination. FTP sensor is located on top of fuel

tank. Repair as necessary. If connector is okay, go to next step.

27) Check FTP Sensor Voltage

Turn ignition on. Using scan tool, select FTP V PID. If FTP V PID is not available on

scan tool, measure voltage between PCM connector pins No. 62 (FTP) and No. 91 (SIG

RTN). If measure voltage or PID voltage is less than .22 volt, go to next step. If voltage

is .22 volt or more, fault is intermittent. Go to TEST Z .



28) Check Opposite Induced High FTP Signal

Turn ignition off. Disconnect FTP sensor connector. Connect a jumper wire between

VREF and FTP terminals at FTP sensor wiring harness connector. Turn ignition on. If

scan tool communication link error is displayed, remove jumper wire and go to next step.

Using scan tool, select FTP V PID. If FTP V PID is not available on scan tool, measure

voltage between PCM connector pins No. 62 (FTP) and No. 91 (SIG RTN). If measured

voltage or PID voltage is not 4-6 volts, remove jumper wire and go to next step. If

voltage is 4-6 volts, replace FTP sensor.

29) Check Voltage At FTP Sensor Connector

Measure voltage between VREF and SIG RTN terminals at FTP sensor wiring harness

connector. See Fig 9. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts,

VREF voltage is out of range. Go to TEST C .

30) Check For Short Circuit


damaged or corroded terminals. Disconnect scan tool from DLC. Measure resistance

between PCM connector pins No. 62 and 103. Also measure resistance between PCM

connector pin No. 62 and negative battery terminal. If both resistance readings are more

than 10,000 ohms, replace PCM. If any resistance reading is 10,000 ohms or less,

repair FTP circuit short to SIG RTN or PWR GND circuit.




33) DTC P0453: Check FTP Sensor Voltage

Turn ignition on. Using scan tool, select FTP V PID. If FTP V PID is not available on

scan tool, measure voltage between PCM connector pins No. 62 (FTP) and No. 91 (SIG

RTN). If measured voltage or PID voltage is more than 4.5 volts, go to next step. If

voltage is 4.5 volts or less, fault is intermittent. Go to TEST Z .

34) Check For Short To Power

Turn ignition off. Disconnect FTP sensor connector, located on top of fuel tank. Turn

ignition on. Measure voltage between FTP terminal at FTP sensor wiring harness

connector and negative battery terminal. See Fig 9. If voltage is 10.5 volts or less, go to

step 36). If voltage is more than 10.5 volts, a short to VPWR exists. Go to next step.

35) Check FTP Circuit For Short To VPWR Circuit


damaged or corroded terminals. Turn ignition on. Measure voltage between PCM

connector pin No. 62 and negative battery terminal. If voltage is more than 10.5 volts,

repair short circuit. If voltage is 10.5 volts or less, replace PCM.

36) Check Opposite Induced Low FTP Signal

Turn ignition off. Connect a jumper wire between SIG RTN and FTP terminals at FTP

sensor wiring harness connector. Turn ignition on. If scan tool communication link error

is displayed, remove jumper wire and go to step 41). Using scan tool, select FTP V PID.

If FTP V PID is not available on scan tool, measure voltage between PCM connector



pins No. 62 (FTP) and No. 91 (SIG RTN). If PID voltage is less than .1 volt, remove

jumper wire and go to next step. If PID voltage is .1 volt or more, unable to induce

opposite signal. Go to step 39).

37) Check Voltage At FTP Sensor Connector

Ensure ignition is on. Measure voltage between VREF and SIG RTN terminals at FTP

sensor wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not

4-6 volts, VREF voltage is out of range. Go to TEST C .

38) Check For Short Circuit


damaged or corroded terminals. Repair as necessary. Measure resistance between

PCM connector pins No. 62 and 90. If resistance is more than 10,000 ohms, replace

FTP sensor. If resistance is 10,000 ohms or less, repair FTP circuit short to VREF

circuit.

39) Check For Open FTP Circuit


damaged or corroded terminals. Repair as necessary. Measure resistance between

PCM connector pin No. 62 and FTP terminal at FTP sensor wiring harness connector. If

resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair

open in FTP circuit.

40) Check For Open SIG RTN Circuit

Measure resistance between PCM connector pin No. 91 and SIG RTN terminal at FTP

sensor wiring harness connector. If resistance is less than 5 ohms, go to next step. If

resistance is 5 ohms or more, repair open in SIG RTN circuit.

41) Check FTP Circuit For Short To VREF Circuit

Measure resistance between PCM connector pins No. 62 and 90. If resistance is more

than 10,000 ohms, replace PCM. If resistance is 10,000 ohms or less, repair FTP circuit

short to VREF circuit.




43) DTC P0457: Check For Missing Or Leaking Fuel Filler Cap

This DTC is set when PCM detects a fuel tank pressure decreases more than 7 in. H O

within 30 seconds after refueling, or excessive purge (fuel vapor) flow more than .06 lbs.

per minute. Possible causes are:

Fuel Filler Cap Not Installed After Refueling (CHECK FUEL CAP Indicator May Be

Illuminated)

Fuel Filler Cap Loose Or Cross-Threaded

Check for missing, cross-threaded or leaking fuel filler cap. Repair or replace as

necessary. Clear DTCs. Perform DRIVE CYCLES under ADDITIONAL SYSTEM

FUNCTIONS. Ensure OBD-II DRIVE CYCLE PROCEDURES are performed to verify

repair. After drive cycle is complete, repeat QUICK TEST . If DTC P0455 or P0457 is

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present, see EVAPORATIVE EMISSIONS SYMPTOMS table under SYSTEM TESTS

(EVAPORATIVE EMISSIONS). If a missing, cross-threaded or leaking fuel filler cap

condition was not found, clear DTCs. Perform DRIVE CYCLES under ADDITIONAL

SYSTEM FUNCTIONS. Ensure OBD-II DRIVE CYCLE PROCEDURES are performed

to verify repair. After drive cycle is complete, repeat QUICK TEST . If DTC P0455 is

present, see EVAPORATIVE EMISSIONS SYMPTOMS table.


This DTC indicates a large fuel vapor leak or no purge flow has been detected. Check

the following for possible cause for this fault:

Faulty aftermarket EVAP system components.

Faulty fuel filler cap.

Faulty fuel vapor hoses or tubes.

Faulty EVAP system components.

CV solenoid partially stuck open.

Faulty Fuel Tank Pressure (FTP) sensor.

Faulty EVAP canister.

If no faults are found, go to next step. If any faults are found, repair as necessary. After

repair is complete, go to next step.






solenoid.

45) Check For EVAP System Leaks Disconnect and plug EVAP return tube (EVAP

canister purge valve-to-intake manifold) at intake manifold vacuum source. Turn ignition

on. Using scan tool, select VPWR PID from PID/DATA monitor menu. If PID voltage is

less than 12 volts, go to step 61). If PID voltage is 12 volts or more, locate evaporative

test port (marked EVAPORATIVE SERVICE PORT) between EVAP canister purge

valve and EVAP canister. If vehicle does not have a test port, go to step 50). Install

EVAP System Leak Tester (134-00056) including compressed gas source (nitrogen or

argon) and pressure regulator to test port. Using scan tool, energize CV solenoid by

entering OUTPUT TEST MODE, and turning all outputs on. Select ALL OFF mode and

press START button on scan tool. Regulate gas pressure on tester to 14 in. H O. Using

instructions provided with EVAP system leak tester, pressurize EVAP system. Follow

system leak test instructions provided with tester. If pressure stays at more than 8 in. H

O, go to next step. If pressure drops to 8 in. H O or less, remove EVAP system leak

tester and go to step 50).

46) Check For Blockage


Pressurize EVAP system to 14 in. H O. Command all outputs OFF. If pressure drops

rapidly, go to step 48). If pressure does not drop rapidly, go to next step.

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47) Check For Blockage Between EVAP Canister Purge Valve & EVAP Canister

Disconnect and plug EVAP canister purge outlet tube (between EVAP canister purge

valve and EVAP canister) at EVAP canister. Re-pressurize system to 14 in. H O.

Remove plug from outlet tube. If system does not immediately lose pressure, remove

blockage or contamination from EVAP canister purge outlet tube, or replace tube. Go to

step 46) to verify repair. If system immediately releases pressure, check the following:




Repair as necessary. Repeat test step 46) to verify repair and go to next step.

48) Check For Blockage Between EVAP Test Port & Fuel Tank


Pressurize EVAP system to 14 in. H O. Remove fuel filler cap. If pressure drops to

zero, leave fuel filler cap off and go to step 56). If pressure does not drop to zero,

remove EVAP system leak tester and go to next step.

49) Check For Blockage Between Fuel Tank & EVAP Canister Tube

Install EVAP system leak tester at fuel filler pipe. Disconnect and plug EVAP canister

tube (from fuel tank) at fuel vapor tee located between EVAP canister purge valve and

EVAP canister (or "F" fitting on canister). Turn ignition on. Pressurize EVAP system to

14 in. H O. Remove plug from EVAP canister tube. If pressure drops, install fuel filler

cap, EVAP canister tube and go to step 56). If pressure does not drop, check the

following:




Repair as necessary. Repeat step 48) to verify repair. Leave fuel filler cap off and go to

step 56).

50) Check For Leaks At Fuel Filler Cap Area

Install EVAP system leak tester to fuel filler pipe. Using scan tool, energize CV solenoid

by entering OUTPUT TEST MODE, and turning all outputs on. Pressurize EVAP system

to 14 in. H O. Follow system leak test instructions provided with tester and check for

leaks around fuel filler cap. If no leak is detected, remove EVAP system leak tester and

install fuel filler cap. Go to next step. If a leak is detected, replace fuel filler cap and

repeat this step to verify repair. If leak is still indicated, go to next step. If no leak is

indicated, testing is complete.

51) Check EVAP Canister

Plug CV solenoid (or filter) or plug canister vent hose. Locate evaporative test port

(marked EVAPORATIVE SERVICE PORT) between EVAP canister purge valve and

EVAP canister and install EVAP system leak tester. Pressurize EVAP system to 14 in.

H O. Using leak detector provided with test kit, check for leakage at EVAP canister and

CV solenoid assembly. If no leak is indicated, go to next step. If a leak is indicated,

repair as necessary. Repeat step 45) to verify repair. If leak is still indicated, go to next

step. If no leak is indicated, testing is complete.

52) Check For Leak Between EVAP Test Port & EVAP Canister


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canister purge valve and EVAP canister (or "F" fitting on canister). Plug or cap fuel

vapor tee (or fitting on canister). Turn ignition on. Using scan tool, access OUTPUT


detector provided with test kit, check for leakage at EVAP return tube between intake

manifold source and EVAP canister. If leak is detected, repair as necessary. After repair

is complete, reconnect all components and go to next step. If no leak is detected, go to

step 54).

53) Verify Repair

Disconnect and plug EVAP return tube (EVAP canister purge valve-to-intake manifold)

at intake manifold vacuum source. Locate evaporative test port (marked EVAPORATIVE

SERVICE PORT) between EVAP canister purge valve and EVAP canister. Install EVAP

system leak tester to test port. Using scan tool, energize CV solenoid by entering

OUTPUT TEST MODE, and turning all outputs on. Select ALL OFF mode and press

START button on scan tool. Regulate gas pressure on tester to 14 in. H O. Using

instructions provided with EVAP system leak tester, pressurize EVAP system. If

pressure stays at more than 8 in. H O remove EVAP system leak tester. Leave fuel

filler cap off and go to step 56). If pressure drops to 8 in. H O or less, remove EVAP

system leak tester and go to next step.

NOTE: Mustang, Ranger, Town Car and Windstar

have a quick disconnect between the EVAP canister

tube and front fuel vapor hose assembly (fuel tank-to-

EVAP canister). This quick disconnect is used as an

alternative location to a fuel vapor tee or "F" fitting on

the EVAP canister for leak check purposes.

54) Check For Leak Between EVAP Canister Tube & Fuel Tank Turn ignition off.


canister purge valve and EVAP canister (or "F" fitting on canister). Plug or cap fuel

vapor tee (or fitting on canister). Install EVAP system leak tester to fuel filler pipe.

Pressurize EVAP system to 14 in. H O. Using leak detector provided with test kit, check

for leakage at the following components:

Fuel filler pipe.

Fuel tank.

Fuel vapor control valve tube assembly.

FTP sensor.

EVAP canister tube between fuel vapor control valve and EVAP canister.

Repair as necessary. After repair is complete, go to next step to verify repair. If no leak

is detected, remove plug from EVAP canister tube. Reconnect EVAP canister tube and

install fuel filler cap. Remove EVAP system leak tester from fuel filler pipe and install at

EVAP test port. Perform step 53) to verify leak no longer exists. After test is complete,

remove fuel filler cap and go to step 56).

55) Verify Repair

Pressurize EVAP system to 14 in. H O. If pressure drops to 8 in. H O or less, leak in

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EVAP system still exists. Repeat step 54) to isolate leak and repair as necessary. If

pressure stays at more than 8 in. H O, remove plug from EVAP canister tube and

reconnect tube. Install fuel filler cap. Remove EVAP system leak tester from fuel filler

pipe and install at EVAP test port. Perform step 53) to verify leak no longer exists. After

test is complete, remove fuel filler cap and go to next step.

56) Check FTP Sensor Operation

Turn ignition on. Using scan tool, select VPWR PID. If PID voltage is 10.5 volts or less,

go to step 61). After completing step, return to this test step and continue testing. If PID

voltage is more than 10.5 volts, select FTP V PID. If PID voltage is 2.4-2.8 volts, go to

next step. If PID voltage is not 2.4-2.8 volts, replace FTP sensor. Repeat this step to

verify repair, then go to next step.

57) FTP Sensor Functional Check

Install EVAP leak tester to fuel filler pipe. Plug canister vent hose or close CV solenoid

to atmosphere by taping CV filter shut. Turn ignition on. Using scan tool, select FTP V

PID. Pressurize EVAP system to 14 in. H O. If PID voltage is 4.2-4.9 volts, remove

EVAP system leak tester. Remove plug from vent hose or remove tape from CV

solenoid filter. Install fuel filler cap and go to next step. If PID voltage is not 4.2-4.9 volts,

replace FTP sensor. Repeat step 56) to verify repair.

58) Check EVAP Canister Purge Valve Operation

Turn ignition off. Remove plug and connect EVAP return tube at intake manifold vacuum

source. Turn ignition on. Using scan tool, select EVAPPDC and FTP V PIDs. Start

engine and observe EVAPPDC PID value. Idle engine until EVAPPD PID reaches 40

percent duty cycle. If FTP V PID voltage is less than 2.6 volts, no problem is indicated at

this time. Testing is complete. If FTP V PID voltage is 2.6 volts or more, go to next step.

NOTE: At high altitude, the intake manifold

vacuum source readings at both the input port

vacuum hose and EVAP return tube must be at least

10 in. Hg.




59) Check Intake Manifold Vacuum To EVAP Canister Purge Valve Turn ignition off.

Disconnect input port vacuum hose and EVAP return tube at EVAP canister purge

valve. See Fig 10 or Fig 11 . Install vacuum gauge to open end of input port vacuum

hose and plug open end of EVAP return tube. Start engine. Note vacuum gauge

reading. Turn ignition off. Install vacuum gauge to EVAP return tube and plug open end

of input port vacuum hose. Start engine and note vacuum gauge reading. If both

vacuum readings are 14-20 in. Hg, replace EVAP canister purge valve. If both vacuum

gauge readings are not 14-20 in. Hg, check for blockage in input port vacuum hose or

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EVAP return tube. Check intake manifold vacuum tree or port for blockage. Repair as

necessary. Repeat step 58) to verify repair.

Fig 10: Identifying EVAP Canister Purge Valve (Escort ZX2, Mustang, Sable & Taurus)




Fig 11: Identifying EVAP Canister Purge Valve (All Other Models)


61) Check Battery Voltage

Turn ignition off. Measure voltage across battery terminals. If voltage is 12 volts or more,

return to step that directed you here and continue EVAP system leak test. If voltage is

less than 12 volts, recharge battery and return to step that directed you here and

continue EVAP system leak test.






65) DTC P1451: Check Voltage To Canister Vent (CV) Solenoid

This DTC indicates an CV solenoid circuit fault. Possible causes are:

Open VPWR circuit.

Open or shorted CV circuit.

Faulty CV solenoid.

Faulty PCM.

Turn ignition off. Disconnect CV solenoid connector. Turn ignition on. Measure voltage

between VPWR terminal at CV solenoid wiring harness connector and negative battery

terminal. See Fig 12. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5

volts or less, repair open in VPWR circuit.

Fig 12: Identifying CV Solenoid Circuits & Connector Terminals


66) Check CV Solenoid Resistance

Turn ignition off. Measure resistance between CV solenoid terminals. If resistance is 48-

65 ohms, go to next step. If resistance is not 48-65 ohms, replace CV solenoid.

67) Check VPWR Circuit Resistance

Measure resistance of VPWR circuit between VPWR terminal at CV solenoid wiring

harness connector and power relay in fuse/relay junction box. Junction box is located in

left side of engine compartment. If resistance is less than 5 ohms, go to next step. If

resistance is 5 ohms or more, repair open in VREF circuit.

68) Check For Open VPWR Circuit

Disconnect PCM connector. Measure resistance of VPWR circuit between PCM



connector pin No. 71 and CV solenoid wiring harness connector. If resistance is less

than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in VPWR

circuit.

69) Check CV Circuit Resistance

Measure resistance of CV circuit between PCM connector pin No. 67 (Sable and Taurus

pin No. 45) and CV terminal at CV solenoid wiring harness connector. If resistance is

less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in CV

circuit.

70) Check CV Circuit For Short To Ground

Turn ignition off. Disconnect PCM connector. Measure resistance between CV terminal

at CV solenoid wiring harness connector and negative battery terminal. If resistance is

more than 10,000 ohms, go to next step. If resistance is 10,000 ohms or less, repair

short to ground in CV circuit.

71) Check CV Circuit Short To PWR Or Chassis Ground

Turn ignition on. Measure voltage between chassis ground and PCM connector pin No.

67 (Sable and Taurus pin No. 45). If voltage is less than one volt, go to next step. If

voltage is one volt or more, repair CV circuit short to VREF, VPWR or chassis ground.




76) DTC P0460: Check Fuel Tank Level

This DTC indicates a Fuel Level Input (FLI) circuit fault. Possible causes are:

Empty fuel tank.

Overfilled fuel tank.

Faulty fuel pump.

Faulty fuel gauge or instrument cluster.

FLI circuit fault.

CASE GND circuit shorted to VPWR.

Faulty PCM.

On Expedition, Mustang, Navigator, Pickup F150 and Pickup - 5.4L Lightning, Town Car

and Windstar, diagnose fuel level indicator or Rear Electronic Module (REM). See

appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT in

appropriate MITCHELL® manual. On all other models, turn ignition on. Note fuel gauge

reading. Using scan tool, select FLI PID. If both fuel gauge and FLI PID readings are

between 1/4 (30 percent for FLI PID) and 3/4 (70 percent for FLI PID), go to step 78). If

readings are not as specified, check fuel tank for leaks. Repair as necessary. If fuel tank

is okay, check for faulty fuse for fuel pump-to-fuel gauge circuit. Proceed as follows:

If DTC P0460 is present, go to next step.

If fuse is blown and DTC P0460 is not present, check for short in VPWR circuit. On

Escort, Mustang and Tracer, go to TEST X . On all other models, go to TEST B .



If fuel gauge is inoperative and DTC P0460 is not present, go to appropriate

INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT in appropriate

MITCHELL® manual and diagnose fuel gauge.

77) Check For Low Fuel Flow

Turn ignition on. While observing both fuel gauge and FLI PID, add 2-3 gallons of fuel to

fuel tank. If fuel gauge or FLI PID reading does not increase, go to step 79). If either

fuel gauge or FLI PID reading increases as fuel is added, drain or fill fuel tank so fuel

level is 30-70 percent full. Clear DTCs. Road test vehicle and repeat QUICK TEST . If

DTC P0460 is still present, go to next step.

78) Check FLI Voltage

Start engine. On Contour, Cougar and Mystique, measure voltage between PCM

connector pins No. 12 (FLI) and 91 (SIG RTN). If voltage is 4.39-6.14 volts, go to step

86). If voltage is not 4.39-6.14 volts, go to next step. On all other models, using scan

tool, select FLI V PID. If PID voltage is not 1.23-2.25 volts, go to next step. If PID

voltage is 1.23-2.25 volts, go to step 87) (Continental) or go to step 86) (all other

models).

79) Check Fuel Pump Module Resistance

Turn ignition off. Disconnect fuel pump module connector. Measure resistance between

FLI and CASE GND terminals at fuel pump module wiring harness connector. See Fig

13-Fig 19 . If resistance is 15-160 ohms, go to next step. If resistance is not 15-160

ohms, check for stuck fuel level float on fuel pump. Repair as necessary. If float moves

freely, replace fuel pump module.

Fig 13: Identifying Fuel Pump Module Circuits & Connector Terminals (Contour, Cougar

& Mystique)




Fig 14: Identifying Fuel Pump Module Circuits & Connector Terminals (Escort & Tracer)


Fig 15: Identifying Fuel Pump Module Circuits & Connector Terminals (Econoline,

Expedition, Navigator & "F" Super-Duty Models)




Fig 16: Identifying Fuel Pump Module Circuits & Connector Terminals (Continental,

Crown Victoria, Explorer, Grand Marquis, Mountaineer, Town Car & Windstar)


Fig 17: Identifying Fuel Pump Module Circuits & Connector Terminals (Ranger Flex

Fuel)




Fig 18: Identifying Fuel Pump Module Circuits & Connector Terminals (Ranger

Gasoline)


Fig 19: Identifying Fuel Pump Module Circuits & Connector Terminals (Sable & Taurus)


80) Check FLI Voltage At Fuel Pump Module

Reconnect all connectors. Disconnect instrument cluster connector to fuel gauge. See

appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT in



appropriate MITCHELL® manual. Start engine and allow to idle. Measure voltage

between FLI terminal at fuel pump module wiring harness connector and negative

battery terminal. If voltage is more than 5 volts, go to next step. If voltage is 5 volts or

less, go to step 82).

81) Check FLI Circuit For Short To VPWR

Turn ignition off. Disconnect PCM connector. Measure voltage between FLI terminal at

fuel pump module wiring harness connector and negative battery terminal. If voltage is

more than 10.5 volts, repair short in FLI circuit. If voltage is not more than 10.5 volts,

replace PCM.

82) Check FLI Circuit For Short To Ground

Ensure ignition is off. Disconnect PCM connector. Measure resistance between PCM

connector pin No. 12 (FLI) or No. 9 (FLI) and negative battery terminal. See Fig 13-Fig

19 . If resistance is more than 10,000 ohms, go to step 84) (Continental) or go to next

step (all other models). If resistance is 10,000 ohms or less, repair short to ground.

83) Check FLI & CASE GND Circuits

Measure resistance between PCM connector pin No. 25 (CASE GND) and pin No. 12

(FLI) or No. 9 (FLI). If resistance is more than 10,000 ohms, go to next step. If

resistance is 10,000 ohms or less, repair short between FLI and CASE GND circuits.

84) Check FLI Circuit For Short To CASE GND (Continental Only)

Locate virtual image instrument cluster Gray 20-pin connector (C256) and 16-pin

connector (C255). See Fig 20. Measure resistance between terminals No. 4 at

connector C256 and terminal No. 28 at connector C255. Also measure resistance

between terminals No. 4 at connector C256 and terminal No. 27 at connector C255. If

both resistance readings are more than 10,000 ohms, go to next step. If any resistance

reading is 10,000 ohms or less, repair short between FLI and FUEL LEVEL RETURN

circuits or FLI and FUEL LOGIC GROUND circuits



Fig 20: Identifying Virtual Image Instrument Cluster Wiring Harness Connector

Terminals (Continental)


85) Check For Open In FLI Circuit

Measure resistance between PCM connector pin No. 12 (FLI) or No. 9 (FLI) and FLI

terminal at fuel pump module wiring harness connector. See Fig 13-Fig 19 . Also



measure resistance between PCM connector pin No. 12 (FLI) or No. 9 (FLI) and FLI

terminal at instrument cluster connector. For instrument cluster connector identification,

see appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT in

appropriate MITCHELL® manual. If both resistance readings are less than 10 ohms, go

to step 87) (Continental) or go to next step (all other models). If any resistance reading

is 10 ohms or more, repair open in FLI circuit

86) Check For Open In CASE GND Circuit

Measure resistance between PCM connector pin No. 25 (CASE GND) and CASE GND

terminal at fuel pump module wiring harness connector. Also measure resistance

between PCM connector pin No. 25 (CASE GND) and fuel gauge ground terminal at

instrument cluster wiring harness connector. If both resistance readings are less than

10,000 ohms, check fuel gauge. See appropriate INSTRUMENT PANELS article in

ACCESSORIES & EQUIPMENT in appropriate MITCHELL® manual. Repair as

necessary. Clear DTCs. Repeat QUICK TEST . If DTC P0460 is still present, replace

PCM. If any resistance reading is 10,000 ohms or more, repair open in CASE GND

circuit.

87) Check For Open In CASE GND Circuit (Continental Only)

Measure resistance between PCM connector pin No. 25 (CASE GND) and terminal No.

27 at virtual image instrument cluster C255 wiring harness connector. See Fig 20. If

resistance is less than 10,000 ohms, repair or replace fuel gauge as necessary. Repeat

QUICK TEST . If DTC P0460 is still present, replace PCM. If resistance is 10,000 ohms

or more, repair open circuit.


occurs at this point. Procedure skips from step 87 to


91) DTC P1441: Monitor Idle Air Control Duty Cycle-Flex Fuel EVAP System

If Continuous Memory DTC P1507 is also present with DTC P1441, go to TEST KE,

step 30). If DTC P1507 is not also present, turn ignition on. Using scan tool, select IAC,

TP and RPM PIDs from PID/DATA monitor menu. With engine at normal operating

temperature, accessories off, and engine idling, IAC PID duty cycle should be 20-45

percent. Observe IAC and RPM PID values for indication of fault while wiggling IAC

valve connector and wiring harness between IAC valve and PCM. Fault will be indicated

by a sudden increase in engine RPM and a decrease in duty cycle. Observe TP PID

value and rapidly depress and release throttle. A fault will be indicated by a slow return

to idle. This may indicate a sticking IAC valve. If any faults are indicated, repair as

necessary. If no faults are found, go to next step.

92) Visually Check EVAP System

Turn ignition off. Check for kinked or pinched fuel vapor tubes/hoses between EVAP

canister, EVAP canister purge valve and intake manifold. Check for cracked or

damaged EVAP canister. Repair as necessary. After repair is complete, go to step

101). If no faults are indicated, go to next step.

93) Check Voltage To EVAP Canister Purge Valve

Disconnect EVAP canister purge valve connector. Turn ignition on. Measure voltage



between VPWR terminal at EVAP canister purge valve wiring harness connector and

negative battery terminal. See Fig 8. If voltage is more than 10.5 volts, go to next step. If

voltage is not more than 10.5 volt, repair open in VPWR circuit.

94) Check For Vacuum At EVAP Canister

Disconnect fuel vapor-to-EVAP canister hose at EVAP canister. Connect a vacuum

gauge to disconnected fuel vapor hose. Start engine and allow to idle for 5 minutes.

Vacuum gauge reading should be zero in Hg. Using scan tool, select EVAPPDC PID

from PID/DATA monitor menu. Ensure vacuum gauge can be seen by vehicle operator.

Road test vehicle at 50-60 MPH. While observing PID value, hold throttle steady for 1-2

minutes with vehicle at a speed more than 50 MPH. When EVAPPDC PID value

reaches 75-85 percent duty cycle, observe vacuum gauge reading. If vacuum gauge

reading changes from about zero in Hg. to about 10 in Hg. with EVAPPDC PID at more

than 75 percent, remove vacuum gauge. Inspect fuel vapor tubes/hoses between EVAP

canister and EVAP canister purge valve for cracks, splits or holes. Also check fuel vapor

tubes/hoses between EVAP canister purge valve and intake manifold. Repair as

necessary and go to next step. If vacuum gauge reading does not change as specified,

remove vacuum gauge. Leave fuel vapor hose disconnected. If vacuum gauge reading

is 6-10 in Hg., go step 96). If vacuum gauge reading is less than 6 in Hg., go to step

97).

95) Check EVAP Canister

Ensure fuel vapor-to-EVAP canister hose at EVAP canister is disconnected. Check all

EVAP canister ports for contamination and blockage. Repair as necessary or replace

EVAP canister. If no faults are found, go to next step.

96) Check For Fuel Vapor Hose Leak

Disconnect other end of fuel vapor-to-EVAP canister hose at EVAP canister purge

valve. See Fig 10 or Fig 11 . Plug open end of fuel vapor hose at EVAP canister.

Connect a vacuum pump to open end of fuel vapor hose at EVAP canister purge valve.

Apply 16 in Hg. to hose. If vacuum holds, remove plug from hose and go to next step. If

vacuum does not hold, replace faulty fuel vapor hose and go to step 101).

97) Check For Fuel Vapor Hose Blockage

Ensure both ends of fuel vapor hose at EVAP canister purge valve and EVAP canister

are disconnected. Connect a vacuum pump to open end of fuel vapor hose at EVAP

canister purge valve. Apply 16 in Hg. to hose. If vacuum holds, fuel vapor hose is

blocked between EVAP canister and EVAP canister purge valve. Repair or replace hose

as necessary. If vacuum does not hold, remove vacuum pump. Reconnect fuel vapor

hose at both ends and go to next step.

98) Check For Intake Manifold Vacuum

Disconnect input port vacuum (to intake manifold) hose at EVAP canister purge valve.

See Fig 10 or Fig 11 . Connect a vacuum pump to input vacuum source port at EVAP

canister purge valve. Apply 10-15 in Hg. If vacuum holds or releases very slowly, repair

EVAP canister purge valve filter blockage or replace EVAP canister purge valve. If

vacuum releases quickly, go to next step.

99) Check For Vacuum At EVAP Canister Purge Valve

Connect EVAP canister purge valve connector. Disconnect input port vacuum (to intake

manifold) hose and fuel vapor-to-intake manifold hose at EVAP canister purge valve.

Connect a vacuum gauge to disconnected input port vacuum (to intake manifold) hose



at EVAP canister purge valve. Start engine and note vacuum gauge reading. Disconnect

vacuum gauge and connect gauge to disconnected fuel vapor-to-intake manifold hose at

EVAP canister purge valve. Start engine and note vacuum gauge reading. If both

vacuum gauge readings are more than 10 in Hg, go to next step. If both vacuum gauge

readings are not more than 10 in Hg, repair cause of vacuum loss. After repair is

complete, go to next step.

100) Check Vacuum Hose & Fuel Vapor Hose

Disconnect input port vacuum (to intake manifold) hose and vapor hose-to-intake

manifold hose at intake manifold. Other end of hoses are still disconnected from

previous step. Connect a vacuum pump to each disconnected hose and apply 16 in Hg.

If vacuum releases for both hoses, replace canister purge valve and go to next step. If

vacuum does not release for one or both hoses, remove blockage or minor kinks in hose

(s). After repair is complete, go to next step.

101) Check EVAP System Leak

Odors in engine compartment or near exhaust system, and engine stalls can be

associated to EVAP system. Possible causes are:

Aftermarket parts and accessories not conforming to EVAP system specifications.

Leaks in EVAP system.

Blockages in EVAP system.

Remove atmospheric vent cap (Blue or Black) on EVAP canister(s) or canister vent line.

Plug (or tape) open vent on EVAP canister(s). Disconnect and plug fuel vapor-to-intake

manifold hose at intake manifold vacuum source. Locate evaporative test port (marked

EVAPORATIVE SERVICE PORT) between EVAP canister purge valve and EVAP

canister. If vehicle does not have a test port, go to next step. Install EVAP System Leak

Tester (134-00056) including compressed gas source (nitrogen or argon) and pressure

regulator to test port. Regulate gas pressure on tester to 27 in. H O. Using instructions

provided with EVAP system leak tester, pressurize EVAP system. Follow system leak

test instructions provided with tester. If system pressure holds, go to next step. If system

pressure does not hold, check fuel filler cap for damage. Replace cap as necessary and

retest. If fuel filler cap is okay, replace EVAP system components (fuel tank, fuel filler

pipe, fuel vapor hoses, etc.) as necessary.

102) Check If Tester Indicates A Leak

Remove fuel filler cap. Turn ignition on. On Mustang, using scan tool, cycle EVAP

canister purge valve open by entering OUTPUT TEST MODE. On all models, regulate

gas pressure on tester to 27 in. H O. Using instructions provided with EVAP system

leak tester, pressurize EVAP system. Follow system leak test instructions provided with

tester. If Red light on tester is on (indicating a system leak), go to next step. If Red light

on tester is off, remove EVAP system leak tester. Clear DTCs. Using scan tool, select

EVAPPDC PID from PID/DATA monitor menu. Road test vehicle 50-60 MPH until PID

value reaches 75 percent duty cycle. Maintain vehicle speed until duty cycle reaches

zero percent. Hold speed for an additional 2 minutes, then stop vehicle. Allow engine to

idle. Retrieve Continuous Memory DTCs. Verify symptom no longer exists.

103) Check For Fuel Vapor Hose Restrictions

Disconnect and plug fuel vapor-to-EVAP canister hose at EVAP canister purge valve.

See Fig 10 or Fig 11 . Using EVAP system leak tester, pressurize EVAP system until

system is stabilized close to 27 in. H O. Record pressure reading. Remove plug from

fuel vapor-to-EVAP canister hose. If pressure drops immediately, remove all plugs and

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go to next step. If pressure does not drop immediately, locate and repair blockages

between fuel tank, EVAP canister purge valve and EVAP canister(s). Remove all plugs

and go to next step.

104) EVAP System Verification

Clear DTCs. Remove fuel filler cap (if not already removed). Disconnect and plug fuel

vapor-to-intake manifold hose at intake manifold vacuum source. Using EVAP system

leak tester, pressurize EVAP system until system is stabilized at about 27 in. H O.

Observe tester leak self-test for 2 minutes and then observe EVAP system leak test.

Listen for vacuum leak noise and check for fuel vapor odors at isolated areas in EVAP

system. If system does not hold pressure, go to next step. If system holds pressure,

reconnect all components. Remove EVAP system leak tester. Clear DTCs. Using scan

tool, select EVAPPDC PID from PID/DATA monitor menu. Road test vehicle 50-60 MPH

until PID value reaches 75 percent duty cycle. Maintain vehicle speed until PID duty

cycle reaches zero percent. Hold speed for an additional 2 minutes, then stop vehicle.

Allow engine to idle. Retrieve Continuous Memory DTCs. Verify symptom no longer

exists.

105) Determine EVAP System Leak

Systematically isolate area of potential pressure leak. Close off pressure to EVAP

system. Disconnect and plug fuel vapor hose from fuel tank at EVAP canister. Using

EVAP system leak tester, pressurize EVAP system until system is stabilized close to 27

in. H O. If pressure now holds, replace EVAP canister. If system does not hold

pressure, close off pressure to EVAP system. Disconnect and plug fuel vapor-to-EVAP

canister hose at EVAP canister purge valve. Again, pressurize EVAP system until

system is stabilized close to 27 in. H O. If system holds pressure, remove plugs.

Reconnect fuel vapor hose at EVAP canister. Return to step 98) to check EVAP

canister purge valve. Replace as necessary. Reconnect all components. Remove EVAP

system leak tester. Clear DTCs. Using scan tool, select EVAPPDC PID from PID/DATA

monitor menu. Road test vehicle 50-60 MPH until PID value reaches 75 percent duty

cycle. Maintain speed until duty cycle reaches zero percent. Maintain speed for an

additional 2 minutes, then stop vehicle. Allow engine to idle. Retrieve Continuous

Memory DTCs. Verify symptom no longer exists. If system does not hold pressure,

remove plugs. Check for fuel vapor hose cracks. Repair as necessary. Remove EVAP

system leak tester. Clear DTCs. Using scan tool, select EVAPPDC PID from PID/DATA

monitor menu. Road test vehicle 50-60 MPH until PID value reaches 75 percent duty

cycle. Maintain vehicle speed until PID duty cycle reaches zero percent. Maintain speed

for an additional 2 minutes, then stop vehicle. Allow engine to idle. Retrieve Continuous

Memory DTCs. Verify symptom no longer exists.

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