Motronic Engine Control Module Power Supply Relay 2 J670, Checking

Motronic Engine Control Module Power Supply Relay 2 J670, Checking

Special tools, testers and auxiliary items required
- Multimeter
- wiring diagrams

Test requirements
- Fuse SB10 OK.
- The Ground (GND) connections at the engine and transmission OK.
- The battery voltage at least 12.5 V.
- The generator OK.

Test procedure
- Perform a preliminary check to verify the customers complaint. Preliminary Check

Start diagnosis
- Using a Multimeter, check the following wiring connection for voltage.

Motronic Engine Control Measure to
Module (ECM) Power Supply
Relay 2 J670 socket
1/30 Engine Ground (GND)

Specified value: 12.5 V

If the specified value was not obtained:
- Check the Motronic Engine Control Module (ECM) Power Supply Relay 2 J670 socket 1/30 to the Battery for an open circuit or short to Ground (GND).
- Check the electrical harness connectors for damage, corrosion, loose or broken terminals.
- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:
- Using a Multimeter, check the following wiring connection for voltage.

Motronic Engine Control Measure to
Module (ECM) Power Supply
Relay 2 J670 socket
3/86 Engine Ground (GND)

- Crank the engine

Specified value: 12.5 V

- Switch the ignition off.

If the specified value was not obtained:
- Check the Motronic Engine Control Module (ECM) Power Supply Relay 2 J670 socket 3/86 to the Motronic Engine Control Module (ECM) Power Supply Relay J271 socket 3/86 for an open circuit or short to Ground (GND).
- Check the electrical harness connectors for damage, corrosion, loose or broken terminals.
- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

Checking Ground (GND)
If the manufacturers test box is being used. Perform the following step.
- Install the test box.

If the manufacturers test box is not being used. Perform the following step.
- Remove the Motronic Engine Control Module (ECM) J623.
- Using a Multimeter, check the following wiring connection for resistance.

Motronic Engine Control Motronic Engine Control Module
Module (ECM) Power Supply (ECM) J623 electrical harness
Relay 2 J670 socket connector T94 or test box socket
4/85 32

Specified value: 1.5 Ohms.

If the specified value was not obtained:
- Check the Motronic Engine Control Module (ECM) Power Supply Relay 2 J670 socket 4/85 to the Motronic Engine Control Module (ECM) J623 electrical harness connector T94 terminal 32 for an open circuit or a short to Battery (+).
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) Power Supply Relay 2 J270.
- Perform a road test to verify repair.

If the fault does not return:
Repair complete, Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
- End diagnosis.

If the fault does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) J623.
- Assembly is performed in the reverse of the removal.

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:

1. Check the DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

End of Diagnosis