ECM 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.

See Appropriate Wiring Diagram Information for component locations and connector views.

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
• Check for any open fuses. If found, locate the short on that circuit and replace the fuse before continuing. Refer to Appropriate Wiring Diagrams for specific circuit information.
• Ignition switched Off

Test Procedure 

-- Remove the ECM Power Supply Relay -J317- from the fuse panel. Refer to Appropriate Wiring Diagrams for location.

Checking the supply voltage

-- Turn the ignition switch ON

-- Using a multimeter, measure the voltage of the ECM Power Supply Relay -J317- 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 ECM Power Supply Relay -J317- for an open circuit or a short circuit. Refer to appropriate System Wiring Diagram information.

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

-- Repair as necessary.

If The Specified Value Was Obtained: 

-- Turn the ignition switch ON

-- Using a multimeter, measure the voltage of the ECM Power Supply Relay -J317- ignition circuit (socket 3/86).

-- Turn the ignition switch OFF

Specified Value: Battery Voltage. 

If The Specified Value Was Not Obtained: 

-- Check the power supply circuit to the ECM Power Supply Relay -J317- for an open circuit or a short circuit. Refer to appropriate System Wiring Diagram information.

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

If The Specified Value Was Obtained: 

Checking wiring

-- Remove the Engine Control Module (ECM) -J623-. Refer to the Repair information for removal and installation procedures.

-- Using a multimeter, measure the resistance of the circuit between the ECM Power Supply Relay -J317- terminal 85 and the Engine Control Module (ECM) -J623- T94/69. Refer to the applicable wiring diagram.

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 ECM Power Supply Relay -J317-.

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 .