Engine Component Power Supply Relay, Checking
Special tools and workshop equipment required
- multimeter.
- wiring diagrams.
Test requirements
- Fuse -SA2- OK.
- The Engine Control Module Power Supply Relay -J271- 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. Refer to PRELIMINARY CHECK .
Start diagnosis
-- Using a multimeter, check the following wiring connection for voltage.
| Engine Component Power Supply Relay -J757- socket | Measure to |
|---|---|
| 2 | Engine Ground (GND) |
Specified value: 12.5 V
If the specified value was not obtained:
-- Check the Engine Component Power Supply Relay -J757- socket 2 to the Battery -A- positive terminal 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:
-- Switch the engine on.
-- Using a multimeter, check the following wiring connection for voltage.
| Engine Component Power Supply Relay -J757- socket | Measure to |
|---|---|
| 8 | Engine Ground (GND) |
Specified value: 12.5 V
-- Switch the engine off.
If the specified value was not obtained:
-- Check the Engine Component Power Supply Relay -J757- socket 8 to Fuse -SB5- \ 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 Engine Control Module (ECM) -J623-. Refer to the appropriate service information.
-- Using a multimeter, check the following wiring connection for resistance.
| Engine Component Power Supply Relay -J757- socket | Engine Control Module -J623- electrical harness connector T94 or test box socket |
|---|---|
| 6 | 72 |
Specified value: 1.5 Ω.
If the specified value was not obtained:
-- Check the Engine Component Power Supply Relay -J757- socket 6 to the Engine Control Module -J623- electrical harness connector T94 terminal 72 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 theEngine Component Power Supply Relay -J757-.
-- 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 and no malfunction is detected in the wiring and the voltage supply was OK:
-- Replace the Engine Control Module (ECM) -J623-. Refer to the appropriate service 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 .