Power Supply Relay 2, Checking
Observe all safety precautions: SAFETY PRECAUTIONS
View clean working conditions: CLEAN WORKING CONDITIONS
Prior to repair work, perform a preliminary check to verify the condition. Refer to PRELIMINARY CHECK .
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 engine control module fuses OK
- Battery voltage at least 12.5 volts
- All electrical consumers switched off
- Vehicles with automatic transmission, shift selector lever in park or neutral
- A/C switched off
- Ground connections between engine/transmission/chassis OK
- Ignition switched off
Test procedure
-- Remove the engine control module power supply relay Power Supply Relay 2 (terminal 15) -J681-.
Checking the supply voltage
-- Turn the ignition switch ON
-- Using a multimeter, measure the voltage of the engine control module power supply relay circuit (socket 1/30).
Specified value: battery voltage.
-- Turn the ignition switch OFF
If the specified value was not obtained:
-- Check the power supply circuit to the engine control module power supply relay Power Supply Relay 2 (terminal 15) -J681- for an open circuit or a short circuit.
-- Check the wiring connections for damage, corrosion, loose or broken terminals.
-- Repair as necessary.
-- Turn the ignition switch ON
-- Using a multimeter, measure the voltage of the engine control module power supply relay ignition circuit (socket 3/86).
Specified value: battery voltage.
-- Turn the ignition switch OFF
If the specified value was not obtained:
-- Check the ignition circuit to the engine control module power supply relay Power Supply Relay 2 (terminal 15) -J681- for an open circuit or a short circuit.
-- Check the wiring connections for damage, corrosion, loose or broken terminals.
Checking wiring
-- Remove the engine control module. Refer to the service information for removal and installation procedures.
-- Using a multimeter, measure the resistance of the circuit between the power supply relay Power Supply Relay 2 (terminal 15) -J681- and the engine control module Engine Control Module (ECM) -J623-. Refer to the applicable wiring diagram.
| Power Supply Relay 2 (terminal 15) -J681- electrical harness connector terminal | Motronic Engine Control Module (ECM) -J623- electrical connector terminal or test box socket or Fuse |
|---|---|
| 2/30 | SB30 |
| 8/87 | SC40 |
| 4/86 | chassis ground |
| 6/85 | T52b/12 of J519 |
Specified value: 1.5 Ω Max.
If the specification was not obtained:
-- Check the wires for a short circuit to each other, a short to battery voltage, and a short to ground.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- Repair as necessary.
If no malfunction is found in the wiring and voltage supply was OK:
-- Replace the engine control module power supply relay Power Supply Relay 2 (terminal 15) -J681-.
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 .