FAULT CODE 482Fuel Pressure Low - Data Valid butBelow Normal Operational Range -

Moderately Severe Level.

Overview

CODE REASON EFFECT

FaultCode: 482PID: P094SPN: 94FMI: 1/18LAMP: AmberSRT:

Fuel Pressure Low - DataValid but Below NormalOperational Range -Moderately Severe Level.

Engine may notstart, whitesmoke, runrough, or losepower.

Fuel System Circuit

Circuit Description

The gear pump draws fuel from the fuel tank through a suctionfuel filter and an anti-drainback valve. The gear pumpdevelops between 1724 and 2620 kPa [250 and 380 psi] offuel pressure. The fuel flows through a pressure fuel filter andfuel shutoff valve to the fueling and timing actuators and railfuel pressure sensor.

Shop Talk

The fuel pressure is monitored by the ECM. If the rail fuelpressure is lower than an acceptable level for a given set ofengine operating conditions, the fault code is logged.

Troubleshooting Steps

STEPS SPECIFICATIONSSTEP1.

Check the fault codes.

STEP 1A. Check for anactive fault code.

Is Fault Code 227 active?

STEP2.

Check the fuel supply.

STEP 2A. Check thevehicle fuel tanks forfuel.

Is there fuel in the fueltanks?

STEP 2B. Check forfuel leaks.

Are there any visible fuelleaks?

STEP 2C. Check fuelinlet restriction.

Is the fuel inlet restrictionless than thespecifications listed?

STEP3.

Check the engineoperation.

STEP 3A. Crank theengine to see if itstarts.

Does the engine start?

STEP4.

Check fuel shutoffvalve operation.

STEP 4A. Check fuelshutoff valve operation.

Does the fuel shutoff valveoperate and is 12-VDCpresent at the terminal ofthe fuel shutoff valve whenthe keyswitch is turnedON?

STEP 4B. Check for amechanical restrictionof the fuel shutoffvalve.

Is debris present in thefuel shutoff valve or arethere signs the fuel shutoffvalve is restricting flow?

STEP5.

Check the fuel lift pumpoperation.

STEP 5A. Check thefuel lift pump foractivation at keyswitchON.

Does the fuel lift pump runwhen the keyswitch isturned ON?

STEP 5B. Check thefuel lift pump pressure.

Is positive fuel pressuregreater than 64 kPa [10psi] present when the liftpump is running?

STEP6.

Check the 1724 kPa[250 psi] fuel pressureregulator.

STEP 6A. Inspect the1724 kPa [250 psi] fuelpressure regulator.

Is there any amount of fuelcoming from the ECMcooling plate supply linewhile the engine is

cranking and the fuelingand timing actuators aredisconnected from theengine harness?

STEP7.

Check the 2620 kPa[380 psi] pressureregulator.

STEP 7A. Inspect the2620 kPa [380 psi]pressure regulator.

Is there more than 237 ml[8 oz] of fuel coming fromthe drain line while theengine is cranking for 15seconds and the fuelingand timing actuators aredisconnected from theengine harness?

STEP8.

Check the fuel pump(gear pump) pressure.

STEP 8A. Measure thefuel pump (gear pump)pressure whilecranking.

Is the fuel pump (gearpump) pressure less than689 kPa [100 psi] crankingat 130 rpm for at least 10seconds after the fuelsystem is primed for 30seconds?

STEP9.

Check the fuelpressure.

STEP 9A. Measure therail fuel pressure.

Is the rail fuel pressure atleast 1448 kPa [210 psi] atidle?

STEP 9B. Measure thefuel pump (gear pump)pressure, enginerunning.

Is the fuel pump (gearpump) pressure aminimum of 1931 kPa [280psi] at 2000 rpm?

STEP10.

Check for air in thepressure-side fuel.

STEP 10A. Check forair in the pressure-sidefuel.

Is air present in thepressure-side fuel?

STEP11.

Check the fuel inletrestriction.

STEP 11A. Measurethe fuel inlet restriction.

Is the fuel inlet restrictionless than thespecification?

STEP12.

Check the fuel shutoffvalve.

STEP 12A. Check for amechanical restrictionof the fuel shutoffvalve.

Is debris present in thefuel shutoff valve or arethere signs the fuel shutoffvalve is restricting flow?

STEP13.

Check the pressurefuel filter.

STEP 13A. Measurethe pressure dropacross the pressurefuel filter.

Is the pressure dropacross the pressure-sidefuel filter less than 517kPa [75 psi]?

STEP14.

Check the 1724 kPa[250 psi] fuel pressure

regulator. STEP 14A. Inspect the

1724 kPa [250 psi] fuelpressure regulator.

Is there any amount of fuelcoming from the ECMcooling plate supply linewhile the engine iscranking and the fuelingand timing actuators aredisconnected from theengine harness?

STEP15.

Check the 2620 kPa[380 psi] pressureregulator.

STEP 15A. Inspect the2620 kPa [380 psi]pressure regulator.

Is more that 237 ml [8 oz]of fuel coming from thedrain line while the engineis cranking for 15 secondsand the fueling and timingactuators aredisconnected from theengine harness?

STEP16.

Check the fuelpressure sensor foraccuracy.

STEP 16A. Verify thefuel pressure sensorfor accuracy.

Does INSITE™ electronicservice tool reading andpressure gauge readingmatch within 138 kPa [20psi]?

STEP17.

Clear the fault codes.

STEP 17A. Disable thefault code.

Fault Code 482 inactive?

STEP 17B. Clear theinactive fault codes.

All fault codes cleared?

Guided Step 1 - Check the fault codes.

Guided Step 1A - Check for an active fault code.

Conditions

Turn keyswitch ONConnect INSITE™electronic service tool.

Action

Check for an active faultcode.

Use INSITE™electronic service toolto read the fault codes.

Note: If Fault Code 482 isactive or inactive, attempt toclear fault. If fault remainsactive or inactive, continuethrough tree.

Is Fault Code 227 active? Is Fault Code 227 active?

YES NONo Repair No Repair

Troubleshoot Fault Code227 Go to 2A

Guided Step 2 - Check the fuel supply.

Guided Step 2A - Check the vehicle fuel tanks forfuel.

Conditions

Turn keyswitch OFF.

Action

Check the vehicle fuel tanksfor fuel.

Verify that there is fuelin the fuel tanks.

Is there fuel in the fuel tanks? Is there fuel in the fuel tanks?

YES NO

No Repair Fill the fuel tank.

Go to 2B Go to 17A

Guided Step 2B - Check for fuel leaks.

Conditions

Turn keyswitch OFF.

Action

Inspect the fuel tanks, lines,and related components forleaks.

Inspect for fuel leaks.

Are there any fuel leaks in thetanks or the fuel supply lines?

Are there any fuel leaks in thetanks or the fuel supply lines?

YES NO

Locate and repair the sourceof the fuel leak by checkingall the engine and OEMsupply lines, fittings, suction-side fuel filter head, fuel tankstand pipes, ECM coolingplate, and ECM cooling platefuel supply and return lines.

No Repair

Go to 17A Go to 2C

Guided Step 2C - Check fuel inlet restriction.

Conditions

Connect vacuumgauge to the suctionside Compuchek™fittingTurn keyswitch ONEngine running at highidle (engine cranking iftroubleshooting No-Start).

Action

If the engine uses a primingpump, wait until the priming

pump has turned off andobserve the reading on thevacuum gauge.

Check the fuel inletrestriction.Refer to Procedure006-020 in Section 6,in theSignature™, ISX,and QSX15 ServiceManual, Bulletin3

Is the fuel inlet restriction lessthan the specifications listed?

Is the fuel inlet restriction lessthan the specifications listedbelow?

YES NO

Dirty - 305 mm-Hg [12 in-Hg];New - 203 mm-Hg [8 in-Hg]

Locate the cause of high fuelinlet restriction. Check thesuction-side fuel filter and fuelsupply lines.

Go to 3A Repair Complete

Guided Step 3 - Check the engineoperation.

Guided Step 3A - Crank the engine to see if itstarts.

Conditions

Turn keyswitch ON.

Action

Crank the engine to see if itstarts.

Start the engine.

Does the engine start? Does the engine start?

YES NONo Repair No Repair

Go to 9A Go to 4A

Guided Step 4 - Check the fuel shutoffvalve.

Guided Step 4A - Check the fuel shutoff valve foractivation at keyswitch ON.

Conditions

Turn keyswitch ON.

Action

Check the fuel shutoff valvefor activation at keyswitchON.

Verify the fuel shutoffoperates and there is12-VDC present at theterminal of the fuelshutoff valve when thekeyswitch is turned on.

Does the fuel shutoff valveoperate and is 12-VDCpresent at the terminal of thefuel shutoff valve when thekeyswitch is turned ON?

Does the fuel shutoff valveoperate and is 12-VDCpresent at the terminal of thefuel shutoff valve when thekeyswitch is turned ON?

YES NO

No RepairRefer to Procedure 019-049 in Section 19 tocheck the fuel shutoffvalve.

Go to 4B Go to 17A

Guided Step 4B - Check for a mechanicalrestriction of the fuel shutoff valve.

Conditions

Turn keyswitch OFF.

Action

Check for a mechanicalrestriction of the fuel shutoffvalve.

Remove and inspectthe fuel shutoff valvefor a mechanicalrestriction.

Is debris present in the fuelshutoff valve or are theresigns the fuel shutoff valve isrestricting flow?

Is debris present in the fuelshutoff valve or are theresigns the fuel shutoff valve isrestricting flow?

YES NO

Repair or replace thefuel shutoff valve.

No Repair

Go to 17A Go to 5A

Guided Step 5 - Check the fuel liftpump operation.

Guided Step 5A - Check the fuel lift pump for

activation at keyswitch ON.

Conditions

Turn keyswitch ON.

Action

Check the fuel lift pump foractivation at keyswitch ON.

Verify the fuel lift pumpruns when the vehiclekeyswitch is turnedON.

Does the fuel lift pump runwhen the keyswitch is turnedON?

Does the fuel lift pump runwhen the keyswitch is turnedON?

YES NO

No Repair

Go to 5B Go to 17A

Guided Step 5B - Check the fuel lift pumppressure.

Conditions

Turn keyswitch ONConnect a pressuregauge on the gearpump inletCompuchek™ fitting.

Action

Check the fuel lift pumppressure.

Verify there is apositive fuel pressuregreater than 64 kPa[10 psi] when the fuellift pump is running.

Note: Erratic fuel lift pumppressure can indicate air inthe fuel.

Is positive fuel pressuregreater than 64 kPa [10 psi]present when the lift pump isrunning?

Is positive fuel pressuregreater than 64 kPa [10 psi]present when the lift pump isrunning?

YES NO

No Repair

Repair or replace the fuel liftpump.

Go to 6A Go to 17A

Guided Step 6 - Check the 1724 kPa[250 psi] pressure regulator.

Guided Step 6A - Inspect the 1724 kPa [250 psi]pressure regulator.

Conditions

Turn keyswitch OFFConnect the enginewiring harness to thefuel shutoff valve.

Action

Inspect the 1724 kPa [250psi] pressure regulator.

Disconnect the wiringharness from thefueling and timingactuators.Remove the fuel linethat connects thepressure fuel filterhead on the integratedfuel system module(IFSM) to the ECMcooling plate at the

cooling plate.Install a cap onto thefitting into the coolingplate to make sure noair is brought into thefuel system.Run the fuel line into abucket and crank theengine. If there is ameasurable amount offuel coming out of theline during cranking,then fuel is bypassingthe 1724 kPa [250 psi]regulator.

Is there any amount of fuelcoming from the ECM coolingplate supply line while theengine is cranking and thefueling and timing actuatorsare disconnected from theengine harness?

Is there any amount of fuelcoming from the ECM coolingplate supply line while theengine is cranking and thefueling and timing actuatorsare disconnected from theengine harness?

YES NO

Remove and inspect the 1724kPa [250 psi] pressureregulator for debris that canstick the regulator open andfor cut or missing o-rings.

Replace the 1724 kPa [250psi] regulator.

No Repair

Go to 17A Go to 7A

Guided Step 7 - Check the 2620 kPa[380 psi] pressure regulator.

Guided Step 7A - Inspect the 2620 kPa [380 psi]pressure regulator.

Conditions

Turn keyswitch OFF

Connect the enginewiring harness to thefuel shutoff valve.

Action

Inspect the 2620 kPa [380psi] pressure regulator.

Disconnect the OEMdrain line connection atthe integrated fuelsystem module (IFSM).Install a short piece ofhose to run into abucket.Disconnect the wiringharness from thefueling and timingactuators.Turn keyswitch ON andwait until the lift pumpstops running.Crank the engine for15 seconds andmeasure the fuel fromthe integrated fuelsystem module (IFSM)drain.

Is more than 237 ml [8 oz] offuel coming from the drain linewhile the engine is crankingfor 15 seconds and thefueling and timing actuatorsare disconnected from theengine harness?

Is more than 237 ml [8 oz] offuel coming from the drainline while the engine iscranking for 15 seconds andthe fueling and timingactuators are disconnectedfrom the engine harness?

YES NO

Remove and inspect the 2620kPa [380 psi] pressureregulator for debris that canstick the regulator open andfor cut or missing o-rings.

Replace the regulator. No Repair

Go to 17A Go to 8A

Guided Step 8 - Check the fuel pump

(Gear Pump) pressure.

Guided Step 8A - Measure the fuel pump (gearpump) pressure while cranking.

Conditions

Connect a pressuregauge to theCompuchek™ fittingon the back of the fuelpump (gear pump)Turn keyswitch ONDisconnect the wire atthe fuel shutoff valve.

Action

Measure the fuel pump(gear pump) pressure whilecranking.

The fuel lift pump mustnot be running duringthis check. Wait 2minutes after thekeyswitch is turned ONor disconnect the 2-pinpower supply from thelift pump.

Note: The engine wiringharness must bedisconnected from the fuelshutoff valve during thisstep.

Measure the fuel pump(gear pump) pressurewhile cranking theengine.

Is the fuel pump (gear pump)pressure less than 689 kPa[100 psi] cranking at 130 rpmfor at least 10 seconds afterthe fuel system is primed for30 seconds?

Is the fuel pump (gear pump)pressure less than 689 kPa[100 psi] cranking at 130 rpmfor at least 10 seconds afterthe fuel system is primed for30 seconds?

YES NO

Repair or replace the fuelpump (gear pump).

No Repair

Go to 17A Go to 17A

Guided Step 9 - Check the fuelpressure.

Guided Step 9A - Measure the fuel pump (gearpump) pressure at idle.

Conditions

Connect allcomponentsTurn keyswitch ONStart the engine.

Action

Measure the fuel pump(gear pump) pressure atidle.

The fuel lift pump mustnot be running duringthis check. Wait 2minutes afterkeyswitch ON ordisconnect the 2-pinpower supply from thefuel lift pump.

Measure the fuel pump(gear pump) pressure.

With the enginerunning at high idle,use a pressure gaugeattached to theCompuchek™ fittingon the back of the fuelpump (gear pump) tomeasure the fuel pump(gear pump) pressure.

Is the fuel pump (gear pump) Is the fuel pump (gear pump)

pressure at least 1448 kPa[210 psi] at idle?

pressure at least 1448 kPa[210 psi] at idle?

YES NONo Repair No Repair

Go to 9B Go to 13A

Guided Step 9B - Measure the fuel pump (gearpump) pressure at high idle.

Conditions

Turn keyswitch ONStart the engine.

Action

Measure the fuel pump(gear pump) pressure athigh idle.

The fuel lift pump mustnot be running duringthis check. Wait 2minutes afterkeyswitch ON ordisconnect the 2-pinpower supply from thefuel lift pump.Measure the fuel pump(gear pump) pressurewith the enginerunning at high idleand no load.Measure the fuel pump(gear pump) pressurewith a pressure gaugeattached to theCompuchek™ fittingon the back of the fuelpump.

Is the fuel pump (gear pump)pressure a minimum of 1931kPa [280 psi] at 2000 rpm?

Is the fuel pump (gear pump)pressure a minimum of 1931kPa [280 psi] at 2000 rpm?

YES NONo Repair No Repair

Go to 16A Go to 10A

Guided Step 10 - Check the air in thepressure-side fuel.

Guided Step 10A - Check for air in the pressure-side fuel.

Conditions

Turn keyswitch OFF.

Action

Check for air in thepressure-side fuel.

Note: Possible sources of airin the pressure-side fuel areleaks in:

OEM supply linesFittingsSuction-side fuel filterheadFuel tank stand pipesECM cooling plateECM cooling plate fuelsupply and return lines.

Is air present in the pressure-side fuel?

Is air present in the pressure-side fuel?

YES NO

Locate and repair the sourceof the air leak by checking allthe OEM supply lines andfittings, suction-side fuel filterhead, fuel tank stand pipes,ECM cooling plate, and ECMcooling plate fuel supply andreturn lines.

No Repair

Go to 17A Go to 11A

Guided Step 11 - Check the fuel inletrestriction.

Guided Step 11A - Measure the fuel inletrestriction.

Conditions

Connect allcomponentsTurn keyswitch ONStart the engine.

Action

Measure the fuel inletrestriction.

The fuel lift pump mustnot be running duringthis check. Wait 2minutes afterkeyswitch ON ordisconnect the 2-pinpower supply from thefuel lift pump.Check the fuel inletrestriction.Maximum clean filter:203 mm Hg [8 in Hg]Maximum dirty filter:305 mm Hg [12 in Hg]

Is the fuel inlet restriction lessthan the specification?

Is the fuel inlet restriction lessthan the specification?

YES NO

No RepairReplace the suction-side fuelfilter or repair the cause ofhigh inlet restriction.

Go to 12A Go to 17A

Guided Step 12 - Check the fuelshutoff valve.

Guided Step 12A - Check for a mechanicalrestriction of the fuel shutoff valve.

Conditions

Turn keyswitch OFF.

Action

Check for a mechanicalrestriction of the fuel shutoffvalve.

Remove and inspectthe fuel shutoff valvefor a mechanicalrestriction.

SMALL | MEDIUM | LARGE

Is debris present in the fuelshutoff valve or are theresigns the fuel shutoff valve isrestricting flow?

Is debris present in the fuelshutoff valve or are theresigns the fuel shutoff valve isrestricting flow?

YES NO

Repair or replace the fuelshutoff valve. No Repair

Go to 17A Go to 13A

Guided Step 13 - Check the pressure-

side fuel filter.

Guided Step 13A - Measure pressure dropacross the pressure-side fuel filter.

Conditions

Connect allcomponentsTurn keyswitch ONEngine running at highidle.

Action

Measure the pressure dropacross the pressure-sidefuel filter.

The fuel lift pump mustnot be running duringthis check. Wait 2minutes afterkeyswitch ON ordisconnect the 2-pinpower supply from thefuel lift pump.

Note: The fuel temperaturemust be a minimum of 38°C[100°F].

Measure the pressuredrop across thepressure-side fuel filterwhile the engine isoperating at high idleand no load.Use the Compuchek™fitting on the back ofthe fuel pump (gearpump) to measure thepressure out of the fuelpump (gear pump).This will be the highpressure reading.Use the Compuchek™fitting on the undersideof the integrated fuelsystem module (IFSM)to measure thepressure of the fuelrail. This will be the lowpressure reading.Subtract the lowreading from the highreading to obtain the

pressure drop acrossthe pressure-side fuelfilter.

Is the pressure drop acrossthe pressure-side fuel filterless than 517 kPa [75 psi]?

Is the pressure drop acrossthe pressure-side fuel filterless than 517 kPa [75 psi]?

YES NO

No Repair Replace the pressure fuelfilter.

Go to 14A Go to 17A

Guided Step 14 - Check the 1724 kPa[250 psi] fuel pressure regulator.

Guided Step 14A - Inspect the 1724 kPa [250 psi]fuel pressure regulator.

Conditions

Turn keyswitch OFFConnect the enginewiring harness to thefuel shutoff valve.

Action

Inspect the 1724 kPa [250psi] fuel pressure regulator.

Disconnect the enginewiring harness from thefueling and timingactuators.Remove the fuel linethat connects thepressure fuel filterhead on the integratedfuel system module(IFSM) to the ECMcooling plate at thecooling plate.Install a cap onto thefitting into the coolingplate to make sure noair is brought into the

fuel system.Run the fuel line into abucket and crank theengine. If there is ameasurable amount offuel coming out of theline during cranking,then fuel is bypassingthe 1724 kPa [250 psi]regulator.

Is there any amount of fuelcoming from the ECM coolingplate supply line while theengine is cranking and thefueling and timing actuatorsare disconnected from theengine harness?

Is there any amount of fuelcoming from the ECM coolingplate supply line while theengine is cranking and thefueling and timing actuatorsare disconnected from theengine harness?

YES NO

Remove and inspect the 1724kPa [250 psi] regulator fordebris that can stick theregulator open and for cut ormissing o-rings.

No Repair

Go to 17A Go to 15A

Guided Step 15 - Check the 2620 kPa[380 psi] fuel pressure regulator.

Guided Step 15A - Inspect the 2620 kPa [380 psi]fuel pressure regulator.

Conditions

Turn keyswitch OFFConnect the enginewiring harness to thefuel shutoff valve.

Action

Inspect the 2620 kPa [380psi] fuel pressure regulator.

Disconnect the OEMdrain line connection atthe integrated fuelsystem module (IFSM).Install a short piece ofhose to run into abucket.Disconnect the wiringharness from thefueling and timingactuators.Turn the keyswitch ONand wait until the liftpump stops running.Crank the engine for15 seconds andmeasure the fuel fromthe integrated fuelsystem module (IFSM).

Is more than 237 ml [8 oz] offuel coming from the drain linewhile the engine is crankingfor 15 seconds and thefueling and timing actuatorsare disconnected from theengine harness?

Is more than 237 ml [8 oz] offuel coming from the drainline while the engine iscranking for 15 seconds andthe fueling and timingactuators are disconnectedfrom the engine harness?

YES NO

Remove and inspect the2620 kPa [380 psi]pressure regulator fordebris that can stick theregulator open and forcut or missing o-rings.Replace the regulator.

No Repair

Go to 17A Go to 16A

Guided Step 16 - Check the fuelpressure sensor for accuracy.

Guided Step 16A - Verify the accuracy of the railfuel pressure sensor.

Conditions

Turn keyswitch OFFInstall a pressuregauge on the rail fuelpressureCompuchek™ fittingTurn keyswitch ONConnect INSITE™electronic service tool.

Action

Verify the readings agree.

Verify the pressuregauge and INSITE™electronic service toolreading for the rail fuelpressure sensor agree.

Does INSITE™ electronicservice tool reading andpressure gauge readingmatch within 138 kPa [20psi]?

Does INSITE™ electronicservice tool reading andpressure gauge readingmatch within 138 kPa [20psi]?

YES NO

No RepairReplace the rail fuel pressuresensor.

Go to 17A Go to 17A

Guided Step 17 - Clear the fault codes.

Guided Step 17A - Disable the fault code.

Conditions

Connect allcomponentsConnect INSITE™

electronic service tool.

Action

Disable the fault code.

Start the engine and letit idle for 1 minute.Use INSITE™electronic service toolto verify Fault Code482 is inactive.

Fault Code 482 inactive? Fault Code 482 inactive?

YES NO

No Repair

Return to the troubleshootingsteps or contact a Cummins®Authorized Repair Location ifall the steps have beencompleted and rechecked.

Go to 17B Go to 1A

Guided Step 17B - Clear the inactive fault codes.

Conditions

Connect allcomponentsTurn keyswitch ONConnect INSITE™electronic service tool.

Action

Clear the inactive faultcodes.

Use INSITE™electronic service toolto clear the inactivefault codes.

All fault codes cleared? All fault codes cleared?

YES NO

No Repair Troubleshooting anyremaining active fault codes

Repair complete Appropriatetroubleshooting steps

Last Modified: 13-Jan-2009