Checking accelerator pedal position sender G79: Audi A3 (AFB, AKN, ARX, ARY, …)

🧭 Before you start

Fits: Audi A3 (8L, 1996–2003)

• Special tools named: V.A.G 1598/31
• Renewed: accelerator position senders

Don't miss

• Connect up the vehicle diagnostic and service information systemVAS 5052 and select the engine electronics control unit. When doing this, the ignition must be switched on.
• The engine control unit converts the voltage values of the angle senders into a percentage referenced to 5 V and displays these percentage values (5 V supply voltage corresponds to 100 %).
• The value displayed in zone 3 must always be roughly twice that in display zone 4.
• Connect the test box V.A.G 1598/31 to the wiring harness to the engine control unit, but do not connect the actual engine control unit .

🔧 Engine codes this applies to

📐 60 workshop diagrams for AFB

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. Connect up the vehicle diagnostic and service information systemVAS 5052 and select the engine electronics control unit. When doing this, the ignition must be switched on.
2. Select the function "“Read measured value block”".
3. Select "“Display group number 062”".
4. Check the specifications for the electronic throttle potentiometer voltages in display zones 3 and 4. [Note: The engine control unit converts the voltage values of the angle senders into a percentage referenced to 5 V and displays these percentage values (5 V supply voltage corresponds to 100 %).]
5. Observe display zones 3 and 4.

6. Slowly floor the accelerator pedal. [Note: The value displayed in zone 3 must always be roughly twice that in display zone 4.]
7. Check voltage supply and wiring of accelerator pedal senders.
8. Remove driver's storage compartment 68.
9. Unplug the connector from the accelerator pedal position sender G79.
10. Switch on ignition.
11. Connect up the multimeter (voltage measuring range) as follows:
12. Check the signal wires.
13. Check wiring between engine control unit and accelerator position senders.
14. Connect the test box V.A.G 1598/31 to the wiring harness to the engine control unit, but do not connect the actual engine control unit .
15. Check for open circuit and short to earth or positive in the following wiring:
16. Eliminate open circuit in wiring/short circuit if necessary.
17. Renew accelerator position senders: Fuel supply system, petrol engines 20.

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