Testing current supply relay for engine control unit — AUDI
Testing current supply relay for engine control unit on Audi: factory workshop procedure for engines ABZ, AEW, AHC, AKG.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📐 18 workshop diagrams for ABZ
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
AEW AHC AKG AKJ AKH
The current supply relay -J271 is located in the electronics box in the plenum chamber.
=> Current Flow Diagrams, Electrical Fault Finding and Fitting Locations binder
Voltage is supplied via this relay to the following components:
Injectors
Engine control unit -J220
Activated charcoal filter solenoid valve -N80
Intake manifold change-over valve -N156
Testing current supply relay:
Detach current supply relay -J271 from relay base.
Connect diode test lamp V.A.G 1527 between contact 2 (positive, terminal 30) and engine earth.
Connect diode test lamp V.A.G 1527 between contact 4 (positive, terminal 30) and engine earth.
The diode test lamp should light up.
If diode test lamp does not light up, check for open circuit in wiring
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations binder
Connect diode test lamp V.A.G 1527 between contact 2 (positive, terminal 30) and contact 6 (earth signal from engine control unit -J220).
Switch on ignition.
The diode test lamp should light up.
If the diode test lamp does not light up.
Switch off ignition.
Connect test box V.A.G 1598/19 to engine control unit wiring harness=>Page
24-15
.
Check for break in wiring connection from contact 6 on relay base to socket A2 of test box.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations binder
If there is no wiring break and diode test lamp still does not light up, renew engine control unit=>Page
24-16
.
Plug current supply relay into relay base.
Connect wiring harness on engine control unit.
Switch on ignition.
Connect diode test lamp to engine earth and to upper contact of each of two fuses.
The diode test lamp should light up, as both fuses conduct voltage on one contact.
If the diode test lamp does not light up for one or both of the fuses, check for break in wiring connection from fuses to contact 8 on current supply relay position.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations binder
If there is no wiring break, renew current supply relay -J271.
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.