Checking accelerator pedal position sender: Audi 1.6 (BAH)

Special tools, workshop equipment, test and measuring appliances and auxiliary items required

V.A.G 1526 Hand multimeter
V.A.G 1594 A Adapter set
V.A.G 1598/22 Test box
Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3A
Current flow diagram

Function

Both accelerator pedal position senders -G79- and -G185- on the accelerator pedal pass the driver's requirements on to the engine control unit independently of one another. Both senders are installed together in a housing.

Check conditions

The fuses must be OK.
The battery voltage must be at least 11.5 V.
All electrical consumers, e.g. lights and rear window heating must be switched off.
If the vehicle is equipped with an air conditioning system, this must be switched off.

Test sequence

Connect fault reader V.A.G 1551 (V.A.G 1552) and with ignition switched on select engine electronics control unit with the "Address word" 01:

=> Repair group 01; General notes on self-diagnosis; Connecting fault reader V.A.G 1551 and selecting engine control unit
4-Cylinder engine (2-valve, roller rockers), Mechanics
General notes on self-diagnosis
Connecting fault reader V.A.G 1551 and selecting engine control unit

Rapid data transfer
HELP
Select function XXX
Indicated on display:

Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

Read measured value block
Input display group number XXX
Indicated on display:

Press keys 0, 6 and 2 for the "Display group number 62" and confirm entry with Q key.

Read measured value block 62
⇒
1
2
3
4
Indicated on display:
(1...4 = Display zones)

Check specifications of sender 1 (G79) at idling stop in display zone 3.
Specification: 12...97 %
Check specifications of sender 2 (G185) at idling stop in display zone 4.
Specification: 4...49 %

Note:

The engine control unit calculates the voltage values of the angle sender in percent relative to 5 Volt and displays these as a percentage figure (5 Volt supply voltage equates to 100 %).

Operate the accelerator pedal slowly until fully depressed and observe the angle sender figures in display zones 3 and 4:

The percent figures in display zone 3 must rise evenly. The tolerance range of 12...97 % is not covered completely.
The percent figures in display zone 4 must rise evenly. The tolerance range of 4...49 % is not covered completely.

Note:

The figure displayed in display zone 3 must always be approximately double that displayed in display zone 4.

Press the ⇒key.
Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
Switch off ignition.

If the display does not indicate as described:

Check accelerator pedal position sender voltage supply and wiring connections =>Page
20-41
.

Checking voltage supply and wiring to control unit

Remove cover in footwell (driver's side).
Pull 6-pin connector off accelerator pedal position sender.
Switch ignition on.
Connect multimeter to measure voltage at the following contacts of the connector:
Contact 1 + earth
Contact 1 + 5
Contact 2 + earth
Contact 2 + 3
Specification: minimum 4.5 V
Switch off ignition.

If the specifications are not obtained:

Remove wiper arms and cowl panel:

=> Electrical system; Repair group 92; windscreen wiper system; removing and installing windscreen wiper system
Electrical system
windscreen wiper system
removing and installing windscreen wiper system

Connect test box V.A.G 1598/22 to control unit wiring harness.

Check wiring for open circuit between test box and 6-pin connector (connector to control unit) using current flow diagram.
Contact 1+socket 6
Contact 2+socket 8
Contact 3+socket 7
Contact 4+socket 33
Contact 5+socket 19
Contact 6+socket 45
Wire resistance: Max. 1.5 ω
Additionally check wires for short to one another, to vehicle earth and to battery positive.
Specification: ∞ω

If no fault is detected in the wiring:

Renew accelerator pedal position sender
=> Page
20-35
, item
4
Interrogating and erasing fault memory:

=> Repair group 01; Fault memory; Interrogating and erasing fault memory of engine control unit
4-Cylinder engine (2-valve, roller rockers), Mechanics
Fault memory
Interrogating and erasing fault memory of engine control unit