Engine Control Module Power Supply Relay, Checking
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- The Engine Control Module (ECM) Power Supply Relay -J271- fuses OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- Vehicles with automatic transmission, selector lever in position "P" or "N".
- A/C switched off.
- Ground connections between engine/transmission/chassis OK.
- Ignition switched OFF.
Test procedure
-- Observe safety precautions. Refer to SAFETY PRECAUTIONS
-- Observe Clean Working Conditions. Refer to CLEAN WORKING CONDITIONS
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK .
Test sequence
-- Remove the Engine Control Module (ECM) Power Supply Relay -J271-.
Checking voltage
-- Turn the ignition switch ON.
-- Using a multimeter, check the Engine Control Module (ECM) Power Supply Relay -J271- socket 30 to ground.
-- Switch the ignition OFF.
Specified value: Battery voltage.
If the specified value was not obtained:
-- Check the wiring and connections in the power supply circuit to the Engine Control Module (ECM) Power Supply Relay -J271- socket 30 for high resistance, an open or short circuit.
-- Check the wiring connections for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If the specified value was obtained:
-- Switch the ignition ON.
-- Using a multimeter, check the Engine Control Module (ECM) Power Supply Relay -J271- socket 86 to ground.
-- Switch the ignition OFF.
Specified value: Battery voltage.
If the specification was Not obtained:
-- Check the wiring from fuse S-15 to relay terminal 86 for an open, high resistance or short circuit to voltage or ground.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If the specified value was obtained:
Checking wiring
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) Power Supply Relay -J271-. Refer to the Repair Information.
-- Using a multimeter, check the Engine Control Module (ECM) Power Supply Relay -J271- to the Engine Control Module (ECM) -J623- electrical harness connector T94 for resistance.
| Engine Control Module (ECM) Power Supply Relay -J271- socket terminal | Engine Control Module (ECM) -J623- electrical connector T94 terminal or test box socket |
|---|---|
| 85 | 69 |
Specified value: 1.5 Ω Max.
If the specification was not obtained:
-- Check the wiring for an open, high resistance or short circuit to voltage or ground.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If the specified value was obtained:
-- Replace the Engine Control Module (ECM) Power Supply Relay -J271-. Refer to the Repair Information.
-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
-- Perform a road test to verify repair.
If the DTC does not return:
Generate readiness code. Refer to READINESS CODE .
If the DTC does return, no malfunction is detected in the wiring and the voltage supply is 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 mentioned 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 .