Check operation of main engine control unit relay
- Make
- Fiat
- Model
- Croma Factory Service Manual
- Year
- 2005–2010
- Section
- Diesel injection system › Check operation of main engine control unit relay
CHECK OPERATION OF MAIN ENGINE CONTROL UNIT RELAY
| STEP | CHECK TO BE PERFORMED | RESOLUTION IF THE CHECK IS NOT OK |
|---|---|---|
| 1 | Turn the ignition key OFF. In the engine compartment junction unit, remove relay T9 (in the middle of the lower row) Turn the ignition key ON. Measure the voltage between Pin 85 of the base unit for relay T9 and the earth, ensuring it is less than 0.3 V. Move on to Step 4 | Move on to Step 2 |
| 2 | If faults are found, restore the wiring between the engine compartment junction unit and the engine compartment junction unit See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Replace the wiring if necessary The test can be considered over | Replace the junction unit Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R. and move on to Step 3 |
| 3 | Check the fault disappears. The test can be considered over | Repair the original junction unit and replace the engine management control unit |
| 4 | Measure the voltage between Pin 87 of the base unit for relay T9 and the earth, ensuring it is less than 1.0 V. Move on to Step 15 | Move on to Step 5 |
| 5 | Turn the ignition key OFF. Disconnect the cable loom connector from the engine management control unit connector A. Turn the ignition key ON. Measure the voltage between Pin 87 of the base unit for relay T9 and the earth, ensuring it is greater than 1.0 V. | Replace the engine management control unit |
| 6 | Turn the ignition key OFF. In the engine compartment junction unit, remove relay T9 (first on the right in the bottom row) Turn the ignition key ON. Measure the voltage between Pin 87 of the base unit for relay T19 and the earth, ensuring it is greater than 1.0 V. | Replace the engine management control unit |
| 7 | Turn the ignition key OFF. Disconnect the cable loom connector from the EGR solenoid Turn the ignition key ON. Measure the voltage between Pin 87 of the base unit for relay T9 and the earth, ensuring it is greater than 1.0 V. | Replace the EGR solenoid valve |
| 8 | Turn the ignition key OFF. Disconnect the cable loom connector from the flow modifying solenoid valve. Turn the ignition key ON. Measure the voltage between Pin 87 of the base unit for relay T9 and the earth, ensuring it is greater than 1.0 V. | Replace the solenoid valve Op. 1064A34 TURBOCHARGER PRESSURE ADJUSTMENT VALVE - R.R. |
| 9 | Turn the ignition key OFF. Disconnect the cable loom connector from the temperature sensor and fuel heating resistance Turn the ignition key ON. Measure the voltage between Pin 87 of the base unit for relay T19 and the earth, ensuring it is greater than 1.0 V. | Replace the fuel heater Op. 1044D10 FUEL HEATER - R + R |
| 10 | Turn the ignition key OFF. Disconnect the cable loom connector from the built-in throttle body actuator. Turn the ignition key ON. Measure the voltage between Pin 87 of the base unit for relay T9 and the earth, ensuring it is greater than 1.0 V. | Replace the throttle casing actuator |
| 11 | Turn the ignition key OFF. Disconnect the cable loom from the brake pedal switch. Turn the ignition key ON. Measure the voltage between Pin 87 of the base unit for relay T9 and the earth, ensuring it is greater than 1.0 V. | Replace the brake pedal switch |
| 12 | Turn the ignition key OFF. Disconnect the battery positive Turn the ignition key ON. Measure the voltage between Pin 87 of the base unit for relay T9 and the earth, ensuring it is less than 1.0 V. | Move on to Step 14 |
| 13 | If faults are present, restore the wiring between the battery positive and the turbine variable geometry control solenoid See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Replace the wiring if necessary The test can be considered over | Replace the solenoid valve Op. 1064B42 SOLENOID CONTROLLING TURBOCHARGER VANE POSITION ACTUATOR - R.R |
| 14 | If faults are present, restore the wiring between the various disconnected components See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Replace the wiring if necessary The test can be considered over | Replace the junction unit Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R. |
| 15 | Turn the ignition key OFF. Disconnect the cable loom connector from the engine management control unit connector A. Check the resistance between Pin 85 of the base unit for relay T9 and the earth is greater than 500 kOhm. Move on to Step 17 | Move on to Step 16 |
| 16 | If faults are found, restore the wiring between the engine compartment junction unit and the engine compartment junction unit See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Replace the wiring if necessary The test can be considered over | Replace the junction unit Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R. |
| 17 | Check that the resistance across Pin 85 of the base of relay T9 and Pin 72 of control unit connector A See M010 ENGINE MANAGEMENT CONTROL UNIT is less than 5 Ohm. Move on to Step 16 | Replace the engine management control unit |
Parts & tools for this job For 2005 Fiat Croma
- PARTEngine gasket setSearch: Fiat Croma 2005 engine gasket set
- TOOLTorque wrenchSearch: 3/8 inch torque wrench
- TOOLFeeler gauge setSearch: feeler gauge set
Links open Amazon search results in a new tab. As an Amazon Associate I earn from qualifying purchases.