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Scania CV AB 2002, Sweden1 585 362

03:02-01Issue 3 en

EDC MS5 for injection pump

Description of operation

RES ACCRET

ON

OFF

MANUALCONTROL

EDC

1 2

EDC

MS5 1 1 8 6 6 8


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2 Scania CV AB 2002, Sweden 03:02-01

ContentsImportant ..................................................................................4

General ..................................................................................5Fuel quantity and injection timing............................6

Communication in the EDC system ..................................................................................9

Components on the engine Component locations on a 9-litre engine................ 10Component locations on a 12-litre engine.............. 11Component locations on a 14-litre engine.............. 11Governor E15 ......................................................... 12Engine speed sensors.............................................. 18Fuel valve V45........................................................20

Needle movement sensor T76 ................................21Charge air pressure and temperature sensors .........22Coolant temperature sensor T33.............................24Junction box............................................................ 25

EDC control unit E12 Function of the EDC control unit ........................... 27EDC control unit, connections ...............................28

Components in the driver area Component locations, truck....................................33Component locations, bus ......................................33Supply relay R34 .................................................... 34Accelerator pedal sensor B25, B26 and D35.....35Control for cruise control S51 ................................ 36Brake pedal switches B1 and B34 .......................... 37Clutch pedal switch B32.........................................38Tachograph O4 .......................................................39Indicator lamp for EDC, W27 or W502 .................40Diagnostics switch with lamp, S52 ........................ 41Switch for temporary increase of engine speed...... 42

Contents


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EDC MS5 for injection pumpImportantThe safety precautions and warnings in the workdescription must be read thoroughly before anywork is carried out.

Using only the work description as a basis forthe work is not permitted.

Important


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03:02-01 Scania CV AB 2002, Sweden 5

GeneralThis booklet describes the EDC MS5. EDC is anacronym for Electronic Diesel Control.

EDC MS5 is an electronic system forcontrolling fuel volume and injection timing.EDC MS5 is fitted to vehicles with an injectionpump.

More information on the fuel system can befound in the following service booklets:

Fuel system, function description, 03:01-01

Fuel system, work description, 03:01-02

Injector for in-line pump system, functionand work description, 03:01-03

General


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Fuel quantity and injection timing

The EDC MS5 determines the fuel volume tosupply to the engine. In certain cases, the EDCMS5 also determines the injection timing. Thiscontrol of the injection means that we canoptimise the combustion, which in turn leads tocleaner exhaust gases and lower fuelconsumption.

The control unit is the brain of the EDCsystem. The control unit processes theinformation from both the sensors and thecomponents that are part of the EDC systemand also from the control units in othersystems. Refer to illustration.

When the control unit has processed theinformation, it sends signals to theelectronically controlled injection pumpgovernor. The signals control the injection ofthe fuel.

The EDC system makes possible suchfunctions as cruise control, hand throttle, speedlimiter, smoke limiter and a special cold startprogramme.

General


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Communication in the EDC system

The EDC control unit is the brain of the EDC system. Below you can see which components the controlunit communicates with and the direction of the information flow.

23

21

22

1

R

N

D

2

20 ARTIC

CONTROL

19

17 15

12

EDC

ABS/TC

OPTICRUISE

RES ACC

RET

ON

OFF

PCDIAGNOS

RET

2 3 4 5 6 7 8 9

10

11

13141618

EDC

1 1 8 4 2 4

1 Supply relay2 Accelerator pedal sensor 3 Brake pedal switches4 Clutch pedal switch5 Control for cruise control6 Tachograph (speed)7 Warning lamp for EDC (truck)8 Warning lamp for EDC (bus)9 Diagnostics switch with lamp10 Diagnostic socket for PC 11 Coolant temperature sensor 12 Charge air temperature sensor

13 Charge air pressure sensor 14 Two engine speed sensors15 Needle movement sensor 16 Fuel valve17 Governor 18 ABS/TC, EBS 19 Retarder 20 Articulation control system21 Exhaust brake22 Automatic gearbox23 Opticruise

Communication in the EDC system


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Components on the engine

Component locations on a 9-litreengine

1 Junction box connecting the EDC controlunit to the EDC components on the engine

2 Needle movement sensor 3 Charge air pressure and temperature

sensor 4 Coolant temperature sensor 5 Auxiliary engine speed sensor (5a on bus)6 Main engine speed sensor (6a on bus)7 Governor (control rack position sensor and

setting solenoids for fuel volume andinjection timing)

8 Fuel valve9 Injection pump

1 2 3 4

5 6

7

8

a a

56

9



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1 Junction box connecting the EDC controlunit to the EDC components on the engine

2 Charge air pressure and temperature sensor(may also be two separate sensors)

3 Auxiliary engine speed sensor 4 Fuel valve5 Injection pump6 Governor (control rack position sensor, main

engine speed sensor and setting solenoid for fuel volume)

7 Coolant temperature sensor

13

7

2

6

4

5


1 Junction box connecting the EDC control unitto the EDC components on the engine

2 Needle movement sensor 3

Coolant temperature sensor 4 Charge air pressure and temperature sensor(may also be two separate sensors)

5 Main engine speed sensor 6 Auxiliary engine speed sensor 7 Governor (control rack position sensor and

setting solenoids for fuel volume and injectiontiming)

8 Fuel valve9 Injection pump

7 85 6

4

1

3

2

9



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Governor E15

The injection pump governor is described here.The injection pump is described in the servicebooklet Fuel system, function description,03:01-01.

The EDC control unit communicates with thefollowing components of the injection pumpgovernor:

One control rack position sensor

One fuel volume setting solenoid

One injection timing setting solenoid On 9and 14-litre engines.

One main engine speed sensor. Only invehicles with 12-litre engines is thislocated in the governor. The sectionEngine speed sensors describes the mainengine speed sensor in vehicles with 9 and14-litre engines.

The components above control the control rack.The components are described below.

1 Governor to regulate the fuel volume2 Injection pump

1 1 8 4 3 0

2 1

1 Governor to regulate the injection timingand fuel volume

2 Injection pump

12

1 1 8 4 2 9



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Control rack position sensor

The control rack position sensor informs theEDC control unit about the control rackposition.

The control rack position sensor consists of aniron core, a measuring coil and a reference coil.

The measuring coil signal reports the controlrack position. The signal changes when thecontrol rack moves.

The reference coil signal allows the control unitto compensate for external factors, such astemperature, that affect the measuring coilsignal. The reference coil signal is not affectedby the motion of the control rack.

1 Iron core2 Measuring coil

3 Control rack 4 Reference coil

0 3

_ 0 5 7 3



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Setting solenoid for fuel volume

The setting solenoid for fuel volume pushes thecontrol rack towards full throttle position. Thesetting solenoid works against the return springthat tries to force the control rack back.

The setting solenoid receives +24 V from thesupply relay and is earthed via EDC controlunit pins 1 and 2.

The control unit regulates the current throughthe solenoid and thus controls the control rack.

Increasing the current pushes the control racktowards full throttle position and vice versa.

If the circuit is broken, the control rack is

forced to the stop position by the return spring.

1 Setting solenoid for fuel volume2 Return spring3 Control rack

1

23

1 1 8 4 2 3



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Injection timing setting solenoid

The injection timing setting solenoid is onlyfitted in certain governors. It turns the prestrokeshaft toward earlier injection timing. It worksagainst the return spring that tries to turn theprestroke shaft back.

The setting solenoid receives +24 V from thesupply relay and is earthed via EDC controlunit pins 3 and 4.

The control unit regulates the current throughthe solenoid and thus controls the prestrokeshaft. If the current increases, the prestrokeshaft is turned towards earlier injection timingand vice versa.

If the circuit is broken, the prestroke shaft isturned back by the return spring, resulting indelayed injection timing.

1 Injection timing setting solenoid 2 Return spring3 Prestroke shaft

The injection timing setting solenoid turns the prestroke shaft toward earlier injection timing.

1

2

3

1 1 8 4 2 2

0 3

_ 0 7 9 9



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Main engine speed sensor

The main engine speed sensor in the governorsenses when a pulse wheel mounted on theinjection pump camshaft is rotating.

If the EDC control unit detects a fault, faultcode 12 is generated.

Note: The sensor is sensitive to polarityreversal and the pins must be connected asindicated below.

Pin 21 signal voltage.

Pin 13 earth.

More information about the following can befound in the section 'Engine speed sensors':

Main engine speed sensor T74. This isfitted in vehicles with EDC MS5 and 9 or14 litre engines.

Main engine speed sensor interaction withauxiliary engine speed sensor.



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Fuel valve V45

The fuel valve is a solenoid valve that is openwhen the power supply is switched on with theignition key. Therefore the voltage should beon when bleeding the fuel system.

The fuel valve receives +24 V from EDCcontrol unit pin 14 and is earthed to the chassis.

The fuel valve is described in more detail in theservice booklet Fuel system, Functiondescription, 03:01-01.

0 3

_ 0 8 0 0



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Needle movement sensor T76

The needle movement sensor integrated in theinjector senses when the nozzle needle opens toallow fuel to be injected into the cylinder. It isused in engines with variable injection timing.Only one of the engine s injectors (cylinder 1)is equipped with a needle movement sensor.The sensor is of inductive type. It is magnetizedby current from the control unit.

The needle movement sensor receives voltagefrom EDC control unit pin 32 and is earthed viapin 17.

0 3

_ 0 7 7 9



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Charge air pressure andtemperature sensors

The charge air pressure and temperaturesensors may either be integrated into a singlecomponent (T47) or consist of two separatecomponents (T31 and T32). However, thefunction of the sensors is the same.

The sensors are described on the next page.

T47 the combined charge air pressure andtemperature sensor.

T31 the charge air pressure sensor.

T32 the charge air temperature sensor.

1 0 7 4 5 6

0 3

_ 0 7 6 8

0 3

_ 0 7 6 9



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Charge air pressure sensor, T47 or T31

The charge air pressure sensor detects theabsolute pressure in the intake manifold, i.e.the atmospheric pressure plus the positivepressure provided by the turbocharger.

The EDC control unit uses the signal from thesensor to limit the fuel quantity when thecharge air pressure is under a certain level. Thelower the pressure, the less fuel the control unitallows the injection pump to distribute. Blacksmoke is avoided in this way.

The sensor receives a supply voltage of +5 Vfrom the EDC control unit pin 33 and is earthedthrough pin 13.

The control unit pin 36 receives a signalvoltage from the sensor. The signal voltage isdirectly proportional to the charge air pressure.High pressure gives high voltage and viceversa.

If there is a fault with the signal, the controlunit operates after a pre-programmed pressurevalue while at the same time generatingfault code 16.

As a safety precaution, the engine torque isthen limited.

Charge air temperature sensor, T47 orT32

The sensor for charge air temperature sensesthe temperature in the intake manifold. TheEDC control unit uses the signal from thesensor to finely adjust the fuel quantity so thatblack smoke is not produced. The warmer thecharge air, the less fuel the control unit allowsout to the unit injectors.

The sensor is of the NTC type, with means thatthe resistance is temperature dependent. If thetemperature increases, the resistance in thesensor drops.

The sensor is earthed via pin 13. The controlunit detects the voltage level between pins 13and 55.

If the voltage is outside a given range, thecontrol unit operates after a pre-programmedtemperature value while at the same timegenerating fault code 15.

The engine will then respond more slowly thannormal to throttle actuation in cold conditions,as the white smoke limiter will not be operatingcorrectly.



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Coolant temperature sensor T33

1 0 6 1 3 2

The coolant temperature sensor affects the fuelquantity when starting the engine. It alsoaffects the engine idling speed and maximumengine speed when the engine is cold.

If the coolant temperature sensor senses thatthe engine is cold when attempting to start(cold start), the following will occur. If theengine does not start within 2 seconds, the fuelquantity injected will successively increaseuntil the engine starts.

Directly after a cold start, the engine speed islimited to 1000 rpm in order to protect theengine the engine idling speed is raised to600 rpm.

The length of time engine speed limitation isengaged varies depending on the coolanttemperature:

The idling speed returns to normal when thecoolant has reached 50 C.

The sensor is earthed via pin 13. The EDCcontrol unit detects the voltage level betweenpins 13 and 53.

If the voltage is outside a given range, thecontrol unit operates after a pre-programmedtemperature value while at the same timegenerating fault code 14.

The engine will then have poorer cold startcharacteristics, the engine idling speed is raisedto 600 rpm and it cannot be adjusted.

Below +10 C 30 secondsAbove +20 C 3 seconds



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Junction box

The junction box on the engine connects theengine s EDC components with the chassiselectrical system. The box protects theconnectors from dirt and mechanical damage.

All EDC components on the engine areequipped with cables that fit into the junctionbox.

0 3

_ 0 7 8 0



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EDC control unit, connections

The EDC control unit is connected to the othercomponents of the EDC system via a 55-pinconnector. Refer to illustration.

The EDC control unit with the 55-pin connector.

3 8

3 9

4 0

4 1

4 2

4 3

4 4

4 5

4 6

4 7

4 8

4 9

5 0

5 1

5 2

5 3

5 4

5 5

2 0

2 1

2 2

2 3

2 4

2 5

2 6

2 7

2 8

2 9

3 0

3 1

3 2

3 3

3 4

3 5

3 6

3 7

1

2

3

4

5

6

7

8

9

1 0

1 1

1 2

1 3

1 4

1 5

1 6

1 7

1 8

1 9

1 1 8 2 1 7

EDC control unit E12


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How the pins are connected is shown below.

1 Earthing the fuel volume settingsolenoid.

2 Earthing the fuel volume setting

solenoid.3 Earthing the injection timing setting

solenoid.4 Earthing the injection timing setting

solenoid.5 Not used.6 Not used.7 Not used.8 Not used.

9 Input signal from the control rackposition sensor measuring coil.10 Input signal from the control rack

position sensor reference coil.11 Power supply to the control rack

position sensor.12 Not used.13 Earth for sensor.14 +24 V supply to the fuel valve.15 +24 V supply from the supply relay to

the control unit.16 +24 V supply from the supply relay to

the control unit.17 Earth for sensor.18 Earthing of the control unit to the

chassis.19 Earthing of the control unit to the

chassis.20 +24 V input signal from the diagnostic

switch. +24 V output signal foractivation of the diagnostic andindicator lamps.

21 Input signal from the main engine speedsensor.

22 Input signal from the auxiliary enginespeed sensor.

23 Input signal for the Limited HandThrottle and Fixed Engine Speedfunctions. The Limited Hand Throttlefunction is activated when the pin isearthed. When pin 41 is earthed at the

same time, the Fixed Engine Speedfunction is activated instead.24 Input signal from brake pedal switch 2.

The control unit interprets an earthedpin as a depressed brake pedal.

25 Input signal from the emergency shut-off switch. An earthed pin will result inan emergency stop of the engine

26 Input signal from the clutch pedalswitch. The control unit interprets anearthed pin as a depressed clutch pedal.

27 Input signal from the potentiometer inthe accelerator pedal sensor. The pinreceives a signal voltage of0.25-4.00 V. The signal voltagedepends on how much the throttle pedalis depressed.

28 Not used (output signal for enginespeed).

29 PWM signal. Output signal for throttleactuation.

30 CAN communication, L cable.31 CAN communication, H cable.32 Input signal from the needle movement

sensor.33 5 V supply to the charge air pressure

sensor.34 The Torque Limiter 2 function is

activated when the pin is earthed. Whenpin 35 is earthed at the same time, theTorque Limiter 3 function is activated

instead.35 The Torque Limiter 1 function is

activated when the pin is earthed. Whenpin 34 is earthed at the same time, theTorque Limiter 3 function is activatedinstead.

36 Input signal from the charge airpressure sensor. The pin receives asignal voltage of 0.33-4.66 V.

37 Not used.

38 Not used.



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39 Input signal from the throttle actuationswitch. If the pin is grounded, thecontrol unit interprets the acceleratorpedal as being depressed.

40 Input signal for disengagement of the

cruise control. +24 V applied to the pindisengages the cruise control.

41 Input signal for the Raised idling speedfunction. If the pin is earthed, theRaised Idling function is activated. Ifpin 23 is earthed at the same time, theFixed Engine Speed function isactivated instead.

42 Input signal for idle speed request.+24 V applied to the pin gives idlingspeed.

43 Input signal from brake pedal switch 1.If the earthing connection is broken, thecontrol unit interprets the brake pedal asbeing depressed.

44 Input signal from the control for thecruise control. The control unit sensesthe voltage level across pins 44 and 13.In vehicles without cruise control, thepin is connected to a resistor. Thecontrol unit interprets the voltage

between pins 44 and 13 as the ONposition for the control for cruisecontrol.

45 +5 V supply to the potentiometer in theaccelerator pedal sensor.

46 Output signal for activation of thesupply relay. The pin earths the relay.

47 +24 V input signal from the starter lockwhen the key is in the drive position.

48 Diagnostics cable K.

49 Diagnostic cable L.50 Not connected. (Input signal for speed

limiter 2. +24 V applied to the pinactivates Speed Limiter 2).

51 Input signal for vehicle speed fromtachograph output D3.

52 Not used. (PWM signal. Input signal forengine control).

53 Input signal from the coolanttemperature sensor. The control unit

detects the voltage level (0.44-4.94 V)between pins 53 and 13.

54 Not used.55 Input signal from the charge air

temperature sensor. The control unitdetects the voltage level (0.44-4.94 V)between pins 55 and 13.



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This text is only here to create an extra page...


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Components in the driverarea

Component locations, truck

1 Accelerator pedal sensor 2 Brake pedal switches3 Clutch pedal switch4 The control for cruise control5 Tachograph (speed)6 Diagnostics switch with lamp7 Warning lamp for EDC 8 Supply relay9 Diagnostic socket for PC

6 7 98

12

54

3 1 0 6 1 2 2

Component locations, bus

1 Diagnostics switch with lamp

2 The control for cruise control3 Clutch pedal switch4 Brake pedal switches5 Accelerator pedal sensor 6 Warning lamp for EDC 7 Tachograph (speed)8 Switch for temporary raising of the engine

speed (Fixed Engine Speed function)9 Diagnostic socket for PC 10 Supply relay

9

2345

6

78

1

10

Components in the driver area


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Supply relay R34

The supply relay acts as the main switch for theEDC system. The EDC control unit is suppliedwith voltage by the supply relay. The controlunit controls the relay itself and this gives itcontrol over the system. If the relay releases,the engine will stop.

When the starter voltage is turned on using thestarter key, voltage is applied to the control unitpin 47 with the battery voltage of +24 V. Thecontrol unit then earths pin 46, the supply relayis activated and the control unit is supplied with+24 V on pins 15 and 16. Location of supply relay in central electric unit.

The central electric unit is the same in bothtrucks and buses.

Location of supply relay and central electricunit, truck. The location of the central electricunit varies in buses.

RP14 RP15 RP16 RP17 RP18 RP19 RP20 RP21 RP22 RP23

RP7 RP8 RP9 RP10 RP11 RP12 RP13

RP1 RP2 RP3 RP4 RP5 RP6

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

1 1 6 3 4 2



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Control for cruise control S51

The different voltage levels of the cruise control functions.

0 3

_ 0 7 6 7

U(volt)

5

4

3

2

1

0

OFF

ON

RET

RES

ACC

1 0 7 4 2 6

Using the control for the cruise control system,the EDC control unit is informed of the speedthe vehicle is required to hold. The control unitreceives continuous information on vehiclespeed from the tachograph.

The control for cruise control is also used whenadjusting idling speed or using the functionsfor the control of engine speed.

The control for cruise control has the followingfive functions.

ON

OFF

ACC (accelerate, the speed of the vehicleincreases)

RET (retard, the speed of the vehicledecreases)

RES (resume, the vehicle returns to thepreviously selected speed)

There are only two cables between the control

and the control unit. The cables are connectedto the control unit pins 13 and 44. Eachfunction gives a certain voltage level (refer tograph) which the control unit senses across thepins.

These voltages are generated as the resistancein the circuit changes, depending on whichfunction is engaged.

The control receives a supply voltage ofapproximately +5 V from control unit pin 44

and is earthed via pin 13.



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Brake pedal switches B1 and B34

Two brake pedal switches sense when the brakepedal is depressed. In buses, the switches areintegrated into one single componentdesignated B1. In trucks, the switches aredesignated B1 and B34. The switches areconnected so that one opens and the othercloses when the pedal is depressed. Theyswitch at the same time when the pedal islightly pressed, i.e. at the start of pedal travel.

The switch that opens when the pedal isdepressed is called brake pedal switch1 and theswitch that closes is called brake pedalswitch 2.

Brake pedal switch 1 is connected between theEDC control unit pin 43 and chassis earth.When the brake pedal is pressed down, theground connection to pin 43 is broken.

Brake pedal switch 2 is connected betweencontrol unit pin 24 and chassis earth. When thepedal is depressed, pin 24 is earthed.

Pedals, truck

1 Brake pedal switch 12 Brake pedal switch 2

2

1

1 1 6 2 4 9

Brake pedal and service brake valve, bus

1 Service brake valve containing brake pedalswitches 1 and 2.

1 1 6 3 8 5

1



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Clutch pedal switch B32

The clutch pedal switch senses when the clutchpedal is depressed.

The switch is connected between the EDC

control unit pin 26 and chassis earth. When thepedal is depressed, the switch closes and earthspin 26.

Pedals, truck

1 Clutch pedal switch. The clutch pedal andits switch look the same in buses.

1

1 1 6 2 5 0



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Indicator lamp for EDC, W27 or W502

The EDC warning lamp comes on for a fewseconds when the starter voltage is switched onwith the starter key and also when the engine isswitched off.

When starter voltage is switched on, thewarning lamp comes on for a few seconds tocheck that it is intact.

When the engine is switched off, the warninglamp comes on while the EDC control unitcarries out a functional check of the EDCsystem. When the check is completed, thesupply relay releases and the warning lamp

goes out. Sometimes, the warning lamp mayflash as part of the functional check; this is nota fault.

When the engine is running, the warning lampshould normally be off. If there is a fault in theEDC system, the warning lamp comes on.

The indicator lamp receives +24 V fromcontrol unit pin 20 and is earthed to the chassis.

Warning lamp for EDC, truck, W27

Warning lamp for EDC, bus, W502.

1 2

0 6 4 4 8

EDC

r/min x 100

1520

25

30

5

10

0

12010080

40

1/210

612

6120 0

21

STOP

1 2

s

1 1 3

1 7 8



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Diagnostics switch with lamp, S52

Using the diagnostics switch, it is possible toextract fault codes that may be stored in theEDC control unit memory. The fault codes areflashed out on the lamp. This switch is alsoused to clear fault codes.

The switch is connected between +24 V batteryvoltage and control unit pin 20. The switch,which is spring-loaded, closes when pressed.

The diagnostic lamp receives +24 V fromcontrol unit pin 20 and is earthed to the chassis.

Pressing in the switch supplies voltage to thelamp.

More about the diagnostics switch, e.g. how tointerpret the flash codes, can be found in thesection Warning system.

The diagnostics lamp is connected in parallelwith the EDC warning lamp and therefore, bothlamps are always on at the same time.

Two types of diagnostics switch, truck.

Diagnostics switch, bus

E D C

E T C

1 1 6 5 3 2

E D C

1 1 6 5 3 3



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Switch for temporary raising of the engine speed (Fixed Engine Speedfunction)

Buses may have a separate switch for the FixedEngine Speed function. Refer to illustration.

The engine speed on a stationery bus can beraised temporarily by activating the switch. Thegearbox must then be in neutral and the parkingbrake applied.

The function is disengaged using the brakepedal, or if fitted, the clutch pedal, exhaustbrake or retarder.

The Scania Programmer can be used toreprogram the fixed engine speed. Moreinformation on the function can be found in thesection Fixed Engine Speed .



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Functions

Emergency stop

The emergency stop function makes it possibleto stop the engine quickly in emergencies suchas an accident when operating a crane.

When the function Emergency stop isactivated, the engine is immediately switchedoff if the vehicle is standing still. Whendriving, the throttle actuation is reduced toidling speed but the engine is not switched off.This allows the continued use of power steeringfor example.

The emergency stop is activated when EDCcontrol unit pin 25 is earthed. Engagement ofthe emergency stop function is set at thefactory; see work description 03:02-02,EDC MS5 for injection pump.

In buses, there is a stop button in the enginecompartment central electric unit connected topin 25.

In control units manufactured until April 1996,fault code 37 is generated each time the

emergency stop is used.

The Emergency Stop function is activated when pin 25 is earthed.

25

EDC

1 1 8 2 2 4

Functions


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Engine speed control

The function is selected by in differentcombinations earthing EDC control unit

pins 23 and 41.

23 41

EDC

1 1 8 2 2 0

Engine speed control is a name common tofour different functions which are used to

control engine speed. The functions aredesignated as follows:

Normal hand throttle, mod 0

Limited hand throttle, mod 1

Raised idling speed, mod 2

Fixed engine speed, mod 3

In normal cases, Normal hand throttle will beused. This means that the engine does not haveany special engine speed restrictions.

The remaining engine speed functions areactivated when EDC control unit pins 23 and41 are earthed in different combinations.

If you want to activate the functions, the pinscan be earthed via a connector located in thecentral electric unit. See work description03:02-02, EDC MS5 for injection pump.

It is possible to connect an extra electricalsystem, so that the correct function isautomatically activated when the unit for theextra system is used.

If several of the functions need to be used, thecontrol unit pins can be earthed in differentcombinations via a switch. More informationon this can be found in the work description03:02-02, EDC MS5 for injection pump.

For a description of how the engine reactswhen each function is activated, see below.

Functions


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Normal hand throttle (mod 0)

The Normal hand throttle function operates sothat the engine maintains the engine speed thatis selected with the control for the cruisecontrol. The function operates in a similar wayto the cruise control the difference beingthat Normal Hand Throttle regulates the enginespeed rather than the vehicle speed.

The engine speed can be regulated between 500and 2000 rpm.

To enable the engine to maintain the selectedengine speed, the EDC control unit controls thefuel injection after first having processedsignals from the engine speed sensors.

Conditions that must be fulfilled before engaging thefunction

EDC control unit pins 23 and 41 must not beearthed.

The control for the cruise control must be in theON position.

The vehicle may not be driven at a speed greaterthan 10 km/h.

How to select the required engine speed

Press RES, the engine will maintain thepreviously selected engine speed.

First press ACC or RET to select a new enginespeed.

Then press RES for at least 3 seconds to store theengine speed.

How to change to idling speed

Press OFFor

depress the brake or clutch pedal

or

activate the exhaust brake or the retarder.

23 41

EDC

1 1 8 2 2 0

Functions


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Limited hand throttle (mod 1)

Using the Limited hand throttle function, it ispossible to select an engine speed and an enginetorque that the engine cannot exceed. The upperlimits can be selected within the following ranges:

700 2000 rpm

minimum 200 Nm, maximum, the maximumengine torque available

In this way, a unit attached to the power take off canbe protected from overloading for example.

The characteristics above are set using ScaniaProgrammer. Using Scania Programmer, it is alsopossible to select whether or not the accelerator pedal

can affect the vehicle when the Limited hand throttleis activated.

Conditions that must be fulfilled before engaging thefunction

The control for the cruise control must be in theON position.

The vehicle may not be driven at a speed greater

than 10 km/h.How to set the upper limits for engine speed andengine torque

Set the upper limits for engine speed and enginetorque in Scania Programmer.

How to activate the upper limits for engine speed andengine torque

IMPORTANT! By reducing the engine speed limit

using the Scania Programmer and earthing the pin asshown below, the engine speed will still increase tothe speed that was set previously. Therefore it canexceed the maximum limit set using ScaniaProgrammer.

Therefore, before using the function, the functionengagement should always be tested. Earth the pin asbelow. Press ACC and then RES for three seconds toset the upper limit according to the ScaniaProgrammer.

Earth pin 23 and ensure that pin 41 in notearthed.

How to set an engine speed below the upper limit

First press ACC or RET to select a new enginespeed.

Then press RES for at least 3 seconds to store theengine speed.

23 41

EDC

1 1 8 2 2 2

Functions


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Raised idling speed (mod 2)

Using the Raised idling speed function, it ispossible to select an engine speed that theengine must never be below. In this way, it ispossible, for example, to fill the compressed airsystem or run the engine until warm. Thefunction can also be used in vehicles equippedwith a cement mixer.

The lower engine speed limit is set with thecontrol for the cruise control between 500and 800 rpm.

Conditions that must be fulfilled beforeengaging the function

The control for the cruise control must bein the ON position.

How to activate the lower limit for the enginespeed

Ensure that EDC control unit pin 23 is notearthed and earth pin 41. The engine speedwill now not drop under the limit that waspreviously set.

Allow the vehicle to idle and set a newlower limit by first pressing ACC or RET.

Then press RES for at least 3 seconds tostore the engine speed.

How to change to normal idling speed

Press OFF or unearth pin 41.

23 41

EDC

1 1 8 2 2 2

How to re-engage the lower limit

If pin 41 is already earthed, only ON needs tobe pressed, followed by RES.

If pin 41 is not earthed, the pin only needs to be

earthed.

Functions


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Fixed engine speed (mod 3)

The fixed engine speed function can, using theScania Programmer, be set with the followingtwo limits for the engine.

An engine torque that the engine cannotexceed. The engine torque can be regulatedbetween 200 and 2000 Nm.

An engine speed that the engine mustmaintain. The engine speed can beregulated between 600 and 2000 rpm.

When these functions are active, the vehiclecannot be affected by using the accelerator orthe control for the cruise control. The functioncan be used when work requiring high

precision is required. i.e. when a crane with along reach is to be used.

Conditions that must be fulfilled before engagingthe function

The vehicle may not be driven at a speedgreater than 10 km/h.

How to set the engine speed and the upper limit forengine torque

Set the engine speed and the upper limit forengine torque in Scania Programmer.

How to activate the engine speed and the upperlimit for engine torque

Earth EDC control unit pins 23 and 41.

How to change to idling speed

Depress the brake or clutch pedal

or

activate the exhaust brake or the retarder.

How to re-engage the limits

Break the earth connection to EDC controlunit pins 23 and 41 and then re-earth them.

23 41

EDC

1 1 8 2 2 3

Functions


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Overview of engine speed control

Shut off criteria

Activation of engine speed control

How to store an engine speed

What can be set using the Scania Programmer

Mod 0 Mod 1 Mod 2 Mod 3

OFF Yes Yes Yes No

>10 km/h Yes Yes No Yes

Brake pedal Yes Yes No Yes

Exhaust brake Yes Yes No Yes

Retarder Yes Yes No Yes

Clutch pedal Yes Yes No Yes

Emergency stop function Yes Yes Yes Yes


ACC, RET or RES Yes Yes Yes No


RES for 3 seconds Yes Yes Yes No

Scania Programmer . No No No Yes

Engine speed range (rpm) 500 2000 500 2000 500 800 600 2000


Maximum engine speed No Yes No Yes

Maximum torque No Yes No Yes

Can the accelerator pedal be used whenengine speed control is active

No Yes No No

Can the engine speed control be usedwhen a gear is engaged

Yes Yes Yes Yes

Functions


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Functions


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No torque limitation (mod 0)

When the No torque limitation function isconnected, the engine torque curve isnormal no special limits are activated.

The engine runs according to the torque curve'No torque limitation (0)' when EDC controlunit pins 34 and 35 are not earthed.

Nm

1 0 7 4 6 0

34 35

EDC

1 1 8 2 2 5

Torque limiter 1 (mod 1)

When the Torque limiter 1 function isactivated, the torque curve of the engine istraditionally peaked. This torque curve maygive the sensation that the pulling powerincreases when the engine speed decreases, i.e.on an uphill slope.

The engine runs according to the torque curve'Torque Limiter (1)' when EDC control unitpin 34 is not earthed and pin 35 is earthed.

Nm

34 35

EDC

1 1 8 2 2 6

Functions


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Speed limitation

It is possible to programme two different speedlimits: Maximum speed and Speed limit 2. The

speed limits are programmed using ScaniaProgrammer.

Below is a more detailed description of the twospeed limits.

Maximum speed

The EDC control unit continuously receivesinformation about the vehicle speed from thetachograph. When the maximum speed isreached, the control unit cuts in and limitsthrottle actuation so that the speed ismaintained.

When driving at the set maximum speed, it ispossible to temporarily increase the enginespeed if the clutch pedal is depressed. Thisfunction is present to facilitate downshiftingwhile engine braking.

Speed limit 2

Speed limit 2 means that it is possible usingScania Programmer to pre-set a speed limitthat is lower than the maximum speed. Thelower speed limit can, for example, be used inrefuse vehicles fitted with an external platform.Speed limit 2 can then be activated whensomeone is standing on the platform.

The default value for Speed limit 2 is 70 km/hwhen a new EDC control unit is installed in avehicle.

Speed limit 2 is activated by applying +24 V toEDC control unit pin 50.

50

EDC

1 1 8 2 2 9

+24V

Functions


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Adjusting idling speed

The idling speed can be adjusted between 500and 700 rpm. Adjustments can be made usingthe control for cruise control . If the vehicle isnot fitted with a control for cruise control, theidling speed can be adjusted using the ScaniaProgrammer or by manufacturing adapterwiring. See Work description 03:02-02,EDC MS5 for injection pump, for a descriptionof how to adjust the idling speed.

Governor type

There are two different types of governor: RQand RQV. When choosing governor type itmust be decided how the EDC control unitshould interpret the signals or messages fromthe accelerator pedal. Below is an explanationof the difference between RQ and RQV.

RQV = the throttle pedal requests a certainengine speed. RQV is used in mostvehicles and is also pre-programmed incontrol units that are ordered as parts.

RQ = the throttle pedal requests a certaintorque. RQ is used in buses equipped withautomatic gearbox. If a new control unit isordered, it must be reprogrammed to RQ.

RQ combined with Opticruise can givesmoother gear changes when the engineload is low.

The governor type can be programmed into thecontrol unit using Scania Programmer.

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Warning system

General

Warning lamp for EDC, truck

Warning lamp for EDC, bus.

1 2

1 0 6 4 4 8

EDC

r/min x 100

1520

25

30

5

10

0

12010080

40

1/210

612

6120 0

21

STOP

1 2

s

If a fault occurs in the EDC system, one ormore of the following measures will be carriedout by the EDC control unit, depending onwhat the fault is.

The warning lamp for EDC comes on. Itwill often go out on its own when the faultceases. Sometimes, however, it may benecessary to switch the starter voltage offand on to get the lamp to go out.

Functions like cruise control and handthrottle are disengaged.

Torque is limited.

When idling, the engine runs at a slightlyhigher engine speed than normal.

The engine is switched off.

The control unit carries out the above measuresin order to prevent the fault causing expensivedamage and at worst leading to uncontrolledthrottle actuation.

If the engine is not turned off, the vehicle canoften be driven to a workshop. It should beremembered, however, that the system hassmaller safety margins than normal, especiallyif engine output is reduced.

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Shutdown test

Every time the engine is switched off, the EDCcontrol unit carries out a special test of theEDC system. While this shutdown test isrunning, the warning lamp is lit. When thecheck is complete, the following occurs: thesupply relay releases, the lamp goes out andthere is no power to the control unit.

If the control unit discovers a fault during theshutdown test, the warning lamp will come onthe next time the engine is started, even if thefault is no longer present. The control unit mustcarry out a fault free shutdown test before thewarning lamp goes out.

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Fault codes

When the control unit discovers a fault, orsomething which it interprets as abnormal, itgenerates a fault code. The warning system cangenerate approximately 30 different fault codes.

Arrangement of flashing codes

The fault codes are flashed out by thediagnostics lamp and are arranged in a certainway. The long flashes of 1 second thatcome first represent units of ten. The shortflashes of 0.3 seconds that followrepresent units of one.

The example on the right signifies fault code 25.

A single very long flash of 4 seconds indicatesthat no fault codes are stored in the memory.

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Fault code memory

The EDC control unit memory has sufficientspace to store 10 fault codes. The fault codesare prioritised between themselves. If the faultcode memory becomes full, higher priorityfault codes can be stored and lower priorityfault codes erased.

The fault codes are stored in two differentplaces in the control unit. Erasing with thediagnostics switch clears the fault codes thatare flashed out on the diagnostics lamp.

However, the fault codes will remain stored inanother memory that can only be accessedusing Scania Diagnos. Scania Diagnos can beused to see how many times each fault hasoccurred; this information can be valuable witha loose connection for example. ScaniaDiagnos is used to erase both fault codememories at the same time.

If the memory that is only accessible by PCbecomes full, new fault codes with low prioritywill not be stored even after clearing the oldfault codes using the diagnostic switch. If theeleventh fault occurs and it has low priority, theindicator lamp will light. The indicator lamp

lights constantly and indicates fault but theflash code memory is empty.

If a fault already stored in the PC memoryoccurs again, a flash code is generated and theindicator lamp lights.

Limp-home mode

If the accelerator pedal sensor potentiometerfails, the vehicle can be driven to a workshop inlimp-home mode. Limp-home mode isactivated by releasing the accelerator pedalonce so that the EDC control unit is aware thatthe throttle actuation switch works.

When the accelerator pedal is then depressedthe throttle actuation switch is closed. Theclosed throttle actuation switch gives a throttleactuation that equals half of full throttle.

When the accelerator pedal is released, theengine will run at idling speed.

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Interaction with other systems

ABS/TC and EBS

The ABS/TC system influences the EDCsystem and vice versa.

The ABS/TC control unit continuously sensesif one of the drive wheels is spinning. TCengine control is activated when the drivewheels spin and the throttle actuation is thenreduced, irrespective of the accelerator pedalposition, until the drive wheels cease to spin.

The EDC control unit continuously sendsinformation on the accelerator pedal position tothe ABS/TC control unit.

The EBS and ABS/TC control unitscommunicate with the EDC control unit in thesame way.

Opticruise

Opticruise influences the EDC system and viceversa.

The Opticruise control unit continuouslyreceives information from the EDC control unitabout data such as engine speed or acceleratorpedal position.

During gear changing, the Opticruise controlunit takes over control of the EDC system andcontrols throttle actuation.

Automatic gearbox

The automatic gearbox receives informationfrom the EDC control unit on throttle actuationand the accelerator pedal position. Whenchanging gear, the automatic gearbox caninfluence the throttle actuation.



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PWM signals

Note: A PWM signal cannot be measured in a reliable way using a normal multimeter.Use the fault codes to locate the cause of anymalfunctions instead.

PWM means that a signal is Pulse WidthModulated. The pulse width may, for example,become greater when the throttle actuationincreases.

The PWM signal is a square wave with aconstant frequency (T). The voltage level (U) isalso constant; the variable is the activation time calculated as a percentage of each cycle(the cycle is shown as 100% in theillustrations).

The PWM signal transmits very accurateinformation.

PWM signal at idling speed.

PWM signal at full throttle.

U

T

10%

100%

U

T

100%

90%

1 0 6 1 6 0



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CAN CommunicationNote: Bodywork builders and coachbuildersmust not connect their own systems to theCAN network without the approval of Scania.If any other equipment other than the factoryfitted equipment is connected, safety andreliability can be affected.

Note: It is not possible to measure or checkCAN messages with a multimeter either. Usethe fault codes to locate the cause of anypossible malfunctions.

CAN is an abbreviation of Controller AreaNetwork. CAN communication is used toreduce the number of cables in the vehicle andat the same time increase reliability. Thecommunication circuit consists of two cables,CAN H (High) and CAN L (Low).

Several different systems are connected tothese two cables and in this way form anetwork. CAN communication is used forexample between EDC, ABS/TC, EBS, theretarder, Opticruise and the coordinator.

In simple terms, CAN communication is ratherlike radio. The data messages that travel alonga CAN cable can be compared to radio wavesthat travel through the air.

When we listen to the radio, the receiver istuned so that only one station can be heard at atime. This is the only station we hear, despitethe fact that many other radio stations arebroadcasting at the same time.

A control unit does approximately the samewith the messages that travel through a CAN

EDCABS/TCOPTICRUISE

1 0 6 1 6 1

circuit in a special memory. This memorycan be compared to a number of radioreceivers, all on at the same time but all set todifferent radio stations in order to hear severalindividual radio programmes at the same time.In this way, the control unit always knows whatis going on.


bomba de inyección. descripción del funcionamiento

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