Checking Diesel direct injection system current supply — AUDI
Checking Diesel direct injection system current supply on Audi: factory workshop procedure for engines AFN. Full factory text, tools and checks.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
🔧 Engine codes this applies to
📐 34 workshop diagrams for AFN
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
The injection system receives its current supply via the Diesel direct injection system relay (J322).
In order for the relay (J322) to close, a voltage must be applied to the Diesel direct injection system control unit via terminal 15. This means that the relay (J322) is only earthed (via the Diesel direct injection system control unit) if a voltage is applied to the control unit via terminal 15.
Test conditions
Battery voltage OK.
Testing voltage supply at terminal 15
Connect test box V.A.G 1598/22 to wiring harness for engine control unit
=> Page
23-29
.
Connect multimeter (voltage test range) between earth and socket 47 of the test box.
Switch ignition on.
Specification: approx. battery voltage
If the specification is not attained:
Check the wiring.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
Testing earth activation for Diesel direct injection system relay -J322
Test conditions
Battery voltage OK.
Terminal 15 voltage supply OK
Open electronics box in plenum chamber.
Switch ignition on.
Specification: Diesel direct injection system relay (electronics box, relay position 3) should pick up.
Note:
The clicking of the valve is difficult to hear and is therefore best checked by touching the relay.
If the relay does not pick up:
Connect test box V.A.G 1598/22 to wiring harness for engine control unit
=> Page
23-29
.
Connect together sockets 1 and 33 on the test box using an auxiliary cable from V.A.G 1594.
Specification: Diesel direct injection system relay (electronics box, relay position 3) should pick up.
If the relay picks up now but not when the control unit is connected:
Replace Diesel direct injection system control unit.
If the relay does not pick up:
Switch off ignition.
Unplug Diesel direct injection system relay -J322 from relay panel (electronics box, relay position 3).
The following wiring connections are to be checked for open circuits and/or short to positive or negative.
Electronics box, relay position 3, contact · Test box V.A.G 1598/22, socket
9 · 33
Rectify any open/short circuit as necessary.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
Testing voltage supply at terminal 30
Test conditions
Battery voltage OK.
Terminal 15 voltage supply OK
Earth activation for relay -J322 OK
Switch off ignition.
Unplug Diesel direct injection system relay -J322 from relay panel (electronics box, relay position 3).
Connect multimeter (voltage test range) between the following contacts on the relay panel:
Electronics box, relay position 3, contact · Specification
2 + earth · approx. battery voltage
If the specification is not attained:
Check the wiring.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
If the specification is attained:
Plug relay back into relay panel (electronics box, relay position 3).
Connect test box V.A.G 1598/22 to wiring harness for engine control unit
=> Page
23-29
.
Connect together sockets 1 and 33 on the test box using an auxiliary cable from V.A.G 1594.
Connect multimeter (voltage test range) between the following contacts on the test box:
Test box V.A.G 1598/22, socket · Specification
2 + 1 · approx. battery voltage
28 + 1 · approx. battery voltage
2 + 27 · approx. battery voltage
28 + 27 · approx. battery voltage
If the specification is not attained:
Check the wiring.
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
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.