Power Supply Relay, 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
• Switch the ignition Off.

Start diagnosis 

-- Remove the Terminal 30 Power Supply Relay -J317-.

Checking the supply voltage 

-- Switch the ignition On.

-- Using a multimeter, measure the voltage of the Terminal 30 Power Supply Relay -J317- circuit (socket 30).

Specified value: battery voltage.

-- Switch the ignition Off.

If the specified value was not obtained: 

-- Check the power supply circuit to the Power Supply Relay (terminal 30) -J317- for an open circuit or a short circuit.

-- Check the wiring connections for damage, corrosion, loose or broken terminals.

-- Repair as necessary.

If the specified value was obtained: 

-- Switch the ignition On.

-- Using a multimeter, measure the voltage of the Power Supply Relay (terminal 30) -J317- ignition circuit (socket 86).

Specified value: battery voltage.

-- Turn the ignition switch OFF

If the specified value was obtained: 

-- Replace the Power Supply Relay (terminal 30) -J317-.

If the specified value was not obtained: 

Checking wiring 

-- Remove the Engine Control Module -J623-.

-- Using a multimeter, measure the resistance of the circuit between the power supply relay Power Supply Relay (terminal 30) -J317- and the engine control module Engine Control Module (ECM) -J623-. Refer to the applicable wiring diagram.

Power Supply Relay (terminal 30) -J317- / Fuse Panel B -SB- electrical harness connector terminal	Engine Control Module (ECM) -J623- electrical connector T94 terminal
61	92
62	69

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 the specified value was obtained: 

If no malfunction is found in the wiring and voltage supply was OK: 

-- Replace the Engine Control Module -J623-.

Final procedures 

After repair work, the following work steps must be performed in the following sequence: 

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .