Motronic Engine Control Module Power Supply Relay -J271-, CHECKING

WARNING: This page is about a different car, the 2010 Audi Q7, 2009 Audi Q7, 2008 Audi Q7, and 2007 Audi Q7. However, it is still accessible from the selected car via links, so may be relevant.

General Description

The following procedure is used to diagnose the Motronic Engine Control Module Power Supply Relay -J271- and the Engine Control Module -J623- power supply voltage that is provided by the Motronic Engine Control Module Power Supply Relay -J271-.

Special tools and workshop equipment required

Multimeter.
Wiring Diagram.
Scan Tool.

Test Requirements

Fuses OK.
Battery voltage OK.
Switch OFF all electrical and electronic accessories.
Vehicles with Auto. Transmission, ensure Selector Lever position is in "P".
Vehicles with Man. Transmission, ensure Shifter Lever position is in "N" with Parking Brake applied.
Coolant Temperature: ≥ 80° C.
Observe all safety precautions: SAFETY PRECAUTIONS .
View clean working conditions: CLEAN WORKING CONDITIONS .
For Hybrid vehicles refer to: HIGH VOLTAGE SYSTEM GENERAL WARNINGS .

Test Procedure

Step	Procedure	Result / Action to Take
1	PERFORM: Preliminary Check to verify the customers complaint. Refer to PRELIMINARY CHECK . -- Was Complaint verified?	-- YES: GO TO: Step 2 -- NO: GATHER more information from customer about the complaint.
2	IGNITION: OFF. DISCONNECT: Motronic Engine Control Module Power Supply Relay -J271-. Refer to appropriate repair information. IGNITION: ON. For 2007 - 2009 MY: CHECK: Motronic Engine Control Module Power Supply Relay -J271- socket terminals C20a and C20d to ground for voltage. For 2010 MY: CHECK: Motronic Engine Control Module Power Supply Relay -J271- socket terminals A2b and A2f to ground for voltage. IGNITION: OFF. SPECIFIED VALUE: Battery voltage. -- Was Value obtained?	-- YES: GO TO: Step 3 -- NO: PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 6
3	REMOVE: Engine Control Module -J623-. Refer to appropriate repair information. For 2007 - 2009 MY: CONNECT: Jumper wire, between the Motronic Engine Control Module Power Supply Relay -J271- socket terminals C20a and C20b. For 2010 MY: CONNECT: Jumper wire, between the Motronic Engine Control Module Power Supply Relay -J271- socket terminals A2b and A2h. IGNITION: ON. CHECK: Engine Control Module -J623- harness connector T94 / 3, T94 / 5, and T94 / 6 to ground for voltage. IGNITION: OFF. SPECIFIED VALUE: Battery voltage. -- Were Values obtained?	-- YES: GO TO: Step 4 -- NO: GO TO: Step 5
4	For 2007 - 2009 MY: REMOVE: Jumper wire, between the Motronic Engine Control Module Power Supply Relay -J271- socket terminals C20a and C20b. For 2010 MY: REMOVE: Jumper wire, between the Motronic Engine Control Module Power Supply Relay -J271- socket terminals A2b and A2h. For 2007 - 2009 MY: CHECK: Motronic Engine Control Module Power Supply Relay -J271- socket terminal C20c to the Engine Control Module -J623- harness connector T94 / 69 for resistance. For 2010 MY: CHECK: Motronic Engine Control Module Power Supply Relay -J271- socket terminal A2d to the Engine Control Module -J623- harness connector T94 / 69 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Was Value obtained?	-- YES: REPLACE: Motronic Engine Control Module Power Supply Relay -J271-. Refer to appropriate repair information. GO TO: Step 6 -- NO: PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 6
5	For 2007 - 2009 MY: REMOVE: Jumper wire, between the Motronic Engine Control Module Power Supply Relay -J271- socket terminals C20a and C20b. For 2010 MY: REMOVE: Jumper wire, between the Motronic Engine Control Module Power Supply Relay -J271- socket terminals A2b and A2h. REMOVE: Appropriate fuse. Refer to the wiring diagram for correct fuse. CHECK: Downstream (output) side of Appropriate fuse. Refer to the wiring diagram for correct fuse to the Engine Control Module -J623- harness connector T94 / 3, T94 / 5, and T94 / 6 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	-- YES: REPLACE: Fuse panel. Refer to appropriate repair information. GO TO: Step 6 -- NO: PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 6
6	Final Procedure Perform a road test to verify repair. -- Does the original DTC return?	-- YES: CHECK: Engine Control Module -J623- harness connector for any damaged, pushed-out pins. REPAIR: As necessary. If all electrical connections are OK: REPLACE: Engine Control Module -J623-. Refer to appropriate repair information. Clear the DTCs. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY . Repair is complete. Generate Readiness Code. Refer to READINESS CODE . Return vehicle to Customer. -- NO: Perform the diagnostic procedure for any DTC's. If no DTC's return, the repair is complete. Return vehicle to customer.