323001963 - 5520CB GLOW HEATER PLUG CONTROL UNIT OPERATION CHECK

STEPCHECK TO BE PERFORMEDREMEDIAL ACTION IF THE CHECK IS NOT OK
1Preheating control unit power supply checkTurn the key to the MAR positionUsing an Examiner in Voltmeter mode, check that there is a 12 V battery voltage between pin 3 and earth    See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Move on to Step 2Restore the electrical continuity of the supply lead    See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Restore the 15 A fuse (F11) in the fuse box after having identified the cause of the problem.Replace main relayReplace the junction unit    Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.
2Check earth connectionDisconnect negative battery cableDisconnect the wiring from the glowheater plugs control unitReconnect the negative battery cableUsing an Examiner In Ohmmeter mode, connect between pin 1 of the wiring and earth    See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Check that the resistance is less than 1 OhmMove on to Step 3Restore the electrical continuity of the earth lead
3Check on preheating control unit activation control by engine control unitTurn the key to the ON positionUsing an Examiner in Voltmeter mode, check that there is a voltage of around 8 V between pin 2 and earth    See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Start the engine and check that the voltage switches to 0 VoltsMove on to Step 4Restore the wiring between the engine management control unit and the preheating control unit.If the voltage is interruptedReplace the engine management control unit    Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - R.R and carry out the correct operation renewal procedure
4Check on return signal from preheating control unit to engine management control unitUsing an Examiner in Voltmeter mode, check that there is a 0 V voltage between pin 5 and earth    See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Start the engine and check that the voltage switches to 12 Volts    See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Move on to Step 5Restore the wiring between the preheating control unit and the engine control unit.If OKReplace glow plug preheating control unit    Op. 5520C20 HEATER PLUGS CONTROL UNIT - R.R and carry out the correct operation renewal procedure
5Check on power supplyCheck that there is a 12 Volt voltage present at pin 30    See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Move on to Step 6Restore the wiring between the preheating control unit and the fuse box on the batteryRestore the 60 A power fuse after having identified what caused it to blow.
6Heater plugs power supply checkStart the engine and check that the battery voltage arrives correctly to the individual glow plugs during the preheating stage    See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT The test can be considered overRestore the wiring between the preheating control unit and the glow heater plugsReplace the preheating control unit    Op. 5520C20 HEATER PLUGS CONTROL UNIT - R.R and carry out the correct operation renewal procedure.
PROCEDURE FOR RESTORING CORRECT OPERATION OF PREHEATING SYSTEMEach time any of the preheating system components (preheating control unit, glow heater plugs, engine management control unit, wiring) is replaced/renewed, a complete heater plugs activation plus heater plugs warning light flashing cycle (described below) should be carried out in order to allow the error in the engine management control unit to be correctly deleted and avoid the heater plugs warning light continuing to flash in the instrument panel even if there is no fault in the preheating system.OPERATING CYCLE:1. Turn the ignition ON and wait until the heater plugs warning light goes out (preheating stage).2. Start the vehicle and wait until the preheating control unit is deactivated (the heater plugs warning light should be off during this stage)3. If there is a fault in the preheating system, the heater plugs warning light should start flashing for 30 seconds.4. At the end of this stage, turn the ignition OFF and repeat the starting process.5. If at the end of the activation of the preheating control unit, the heater plugs warning light no longer flashes (defect no longer present), delete the error from the memory using the Examiner.
Heater plugs control unit
ComponentPin
Glow heater plug 1 -G1
Glow heater plug 2 -G2
Glow heater plug 3 -G3
Glow heater plug 4 -G4
N.C.G5
Earth31
Preheating control unit controlK
+ 15 Supply86
N.C.ST
Feedback signalDi
Power supply+30 Batt (Threaded pin)