Power Supply Relay, Terminal 30, B+ Checking
Special tools and workshop equipment required
- Multimeter.
- Wiring diagrams.
Test requirements
- Fuse -SA1- OK.
- Fuse -SB23- OK.
- The Ground 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. Refer to PRELIMINARY CHECK .
Start diagnosis
-- Using a multimeter, check the following wiring connection for voltage.
| Power Supply Relay (terminal 30, B+) -J317- socket | Measure to |
|---|---|
| 30 | Engine Ground |
Specified value: 12.5 V
If the specified value was Not obtained:
-- Check the Power Supply Relay (terminal 30, B+) -J317- socket 30 to the Battery positive for an open circuit, high resistance or short to Ground.
-- Check the electrical harness connectors for damage, corrosion, loose or broken terminals.
-- If necessary, repair the wiring connection.
If the specified value was obtained:
-- Using a multimeter, check the following wiring connection for voltage.
| Power Supply Relay (terminal 30, B+) -J317- socket | Measure to |
|---|---|
| 85 | Engine Ground |
Specified value: 12.5 V
If the specified value was Not obtained:
-- Check the Power Supply Relay (terminal 30, B+) -J317- socket 85 to Battery positive for an open circuit, high resistance or short to Ground.
-- Check the electrical harness connectors for damage, corrosion, loose or broken terminals.
-- If necessary, repair the wiring connection.
If the specified value was obtained:
Checking Ground
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 Engine Control Module (ECM) -J623-. Refer to the Repair Information.
-- Using a multimeter, check the following wiring connection for resistance.
| Power Supply Relay (terminal 30, B+) -J317- socket | Motronic Engine Control Module (ECM) -J623- electrical harness connector T121 or test box socket |
|---|---|
| 86 | 23 |
Specified value: 1.5 Ω.
If the specified value was Not obtained:
-- Check the Power Supply Relay (terminal 30, B+) -J317- socket 86 to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T121 terminal 23 for an open circuit, high resistance or a short to Battery (+).
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the wiring connection.
If the specified value was obtained:
-- Replace the Power Supply Relay (terminal 30, B+) -J317-.
-- Perform a road test to verify repair.
If the fault does not return:
Generate readiness code. Refer to READINESS CODE .
If the fault does return, no malfunction is detected in the wiring and the voltage supply was OK:
-- Replace the Engine Control Module (ECM) -J623-. Refer to the Repair Information.
-- Assembly is performed in the reverse of the removal.
Final procedures
After repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .