Testing secondary air pump replay: Audi 2.8 (ACK, ALG, APR, AQD)
Step-by-step testing secondary air pump replay for the Audi 2.8: factory workshop text. What to remove, in what order, and what to check after.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📐 28 workshop diagrams for ACK
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
APR
Unplug 2-pin connector from secondary air pump motor and connect diode test lamp V.A.G 1527 to disconnected connector using test leads from V.A.G 1594.
Start final control diagnosis and select secondary air pump relay -J299
=>Page
01-37
.
Notes:
This test can give three possible results; these are described below:
1st possible result: diode test lamp flashes
This means that the supply voltage at the relay is OK (both the power circuit and the relay control circuit) and the activation via the engine control unit is working properly, so the relay is supplying power to the motor. The fault is in the secondary air pump motor=>Page
24-102
(top).
Please note that the final control diagnosis will stop after about 1 minute. To repeat the final control diagnosis, start the engine, switch off the ignition and then switch on again.
2nd possible result: diode test lamp does not flash but secondary air pump relay clicks.
This means that the supply voltage for the relay control circuit is OK and the activation via the engine control unit is working properly. The fault can be in the supply voltage for the relay power circuit (fuse), an open circuit in the wiring between the fuse and the secondary air pump, the earth connection to the secondary air pump, or in the relay itself=>Page
24-102
(centre).
3rd possible result: diode test lamp does not flash and secondary air pump relay does not click.
This means that the supply voltage for the relay control circuit is not OK or the activation via the engine control unit is not working. The fault may also be in the relay itself (open circuit in relay coil)=>Page
24-103
1st possible result: diode test lamp flashes
Renew secondary air pump motor (V101):
=> 6-cylinder engine (5-valve), Mechanics; Repair group 26; Secondary air system; Removing and installing parts of secondary air system
6-cylinder engine (5-valve), Mechanics
Secondary air system
Removing and installing parts of secondary air system
2nd possible result: diode test lamp does not flash but secondary air pump relay clicks.
Check fuse for secondary air pump relay -J299.
=> Current flow diagrams, Electrical fault-finding and Fitting locations
If the fuse is not faulty:
Remove secondary air pump relay from relay carrier.
=> Current flow diagrams, Electrical fault-finding and Fitting locations
Notes:
If tools are necessary to pull relays or control units out of the relay plate, first disconnect battery earth strap.
Before disconnecting battery earth strap obtain code for radios with anti-theft coding.
Test voltage supply (terminal 30) to relay using current flow diagram. If necessary, renew secondary air pump relay -J299.
3rd possible result: diode test lamp does not flash and secondary air pump relay does not click.
Switch off ignition.
Connect test box V.A.G 1598/31 to wiring harness for engine control unit=>Page
24-21
. Do not connect engine control unit.
Test for open circuit in wiring between socket 46 of test box and relay carrier for secondary air pump rely (use current flow diagram).
If no fault in wire is detected:
Renew engine control unit => Page
24-24
.
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.
Ask about my car →Other AUDI procedures
- Aligning tailpipes - vehicles with visible tailpipes · 1 torque figures
- Renewing engine control unit – VW Passat B5
- Servicing valve gear
- Checking fuel system for leaks – Audi R8
- Installing lower part of sump - vehicles with solid gasket · 1 torque figures
- Removing and installing toothed belt – Audi · 56 torque figures
- Removing engine – Audi A8 D3 · 41 torque figures
- Removing camshaft timing chain from camshafts – Audi A6/A7 C7 · 38 torque figures
- Installing engine – Audi A8 D4 · 36 torque figures
- Removing and installing camshaft timing chain · 29 torque figures
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.