Power Supply Relay 2, Checking
Observe all safety precautions: SAFETY PRECAUTIONS
View clean working conditions: CLEAN WORKING CONDITIONS
Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.
For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.
Special tools and workshop equipment required
- multimeter.
- Wiring diagram.
Test requirements
- The Motronic Engine Control Module (ECM) - J623- 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 (GND) connections between engine/transmission/chassis OK.
- Ignition switched off.
Test procedure
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK
Start diagnosis
-- Remove the Power Supply Relay 2 (terminal 15) -J681-. Refer to appropriate service information.
Checking voltage
-- Using a multimeter, check the Power Supply Relay 2 (terminal 15) -J681- socket 2/30 to Ground (GND).
Specified value: battery voltage.
If the specified value was not obtained:
-- Check the wiring connections from the Battery to the Power Supply Relay 2 (terminal 15) -J681- socket 2/30 for an open circuit or a 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 Power Supply Relay 2 (terminal 15) -J681- socket 6/85 to Ground (GND).
Specified value: battery voltage.
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 Motronic Engine Control Module (ECM) -J623-. Refer to appropriate service information.
-- Using a multimeter, check the Power Supply Relay 2 (terminal 15) -J681- socket 3/86 to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T94 terminal 92 for resistance.
| Power Supply Relay 2 (terminal 15) -J681- socket terminal | Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminal or test box socket |
|---|---|
| 3/86 | 92 |
Specified value: 2.0 Ω Max.
If the specification was not obtained:
-- Check the wiring for a short circuit to Battery (+), or an open circuit.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If no malfunction is found in the wiring:
Checking activation
-- Switch the ignition on.
-- Using a multimeter, check the Power Supply Relay 2 (terminal 15) -J681- socket 4/85 to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T94 terminal 69 for voltage.
| Power Supply Relay 2 (terminal 15) -J681- socket terminal | Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminal or test box socket |
|---|---|
| 4/85 | 69 |
-- Switch the ignition off.
Specified value: 0.5 V Max.
If the specified value was obtained:
-- Replace the Power Supply Relay 2 (terminal 15) -J681-. Refer to appropriate service information.
If the specified value was not obtained:
-- Check the wiring for a short circuit to Battery (+), or an open circuit.
-- Check the wiring connection for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If no malfunction is found in the wiring and voltage supply was not OK:
-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to appropriate service information.
Final procedures
After the 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 .