Checking angle sensor for throttle valve actuator: Audi 2.4 (APS, APZ, ARJ)

APZ ARJ
Special tools, testers and workshop equipment required

V.A.G 1526 A
V.A.G 1594 A
V.A.G 1598/31
VAS 5051 with VAS 5051/1

or

V.A.G 1551 with V.A.G 1551/3 A

The throttle valve drive angle sensors -G187 and -G188 signal the position of the throttle valve to the engine control unit. Both angle sensors are located in the throttle valve control unit.

Test sequence

Connect up vehicle diagnosis, measurement and information system VAS 5051 or fault reader V.A.G 1551 and select engine electronics control unit with "Address word" 01 => Page
01-3
.
When doing this the ignition must be switched on.

Rapid data transfer
HELP
Select function XX
Display readout:

Enter "08" to select the function "Reading measured value block" and confirm entry with Q key.

Reading measured value block
Q
Enter display group number XXX
Display readout:

Enter "062" to select "Display Group 062" and confirm entry with the Q key.

Read measurement block 62
⇒
1
2
3
4
Display readout:

Check specified values for electronic throttle potentiometer voltages.

Display zones
1 · 2 · 3 · 4
Display Group 062: Electronic throttle potentiometer voltages
Display · xx % · xx % · xx % · xx %
Display · Throttle valve angle / (angle sensor 1) · Throttle valve angle / (angle sensor 2) · Sensor for / accelerator pedal position · Sensor 2 for / accelerator pedal position
Range · 0...100 % · 0...100 % · 0...100 % · 0...50 %
Specified value · 3...93 % · 97...3 % · 12...97 % · 4...49 %

Note:

The engine control unit converts and displays the voltage readings from the angle sensors as percentages of 5 V. (A 5 Volt supply corresponds to 100%).

Observe readouts in display fields 1 and 2.
Slowly depress accelerator pedal.

Percentage displayed in zone 1 should rise evenly. The tolerance range from 3...93% is not fully utilised.

Percentage displayed in zone 2 should fall evenly. The tolerance range from 97...3% is not fully utilised.

Notes:

The reason why the value in display zone 1 rises and that in zone 2 falls is that the potentiometers (angle sensors) in the throttle valve control unit operate in opposite directions.
This means that the voltage picked off by one of the angle sensors runs in the direction of 5 V. (As the throttle is opened, the voltage becomes greater and the percentage increases).
The voltage picked off by the angle sensor 2 runs from 5 V in the direction of 0 V. (As the throttle is opened, the voltage becomes smaller and the percentage decreases).

If the displays are not as described:

Check throttle valve control unit voltage supply and wiring => Page
24-142
. Pay particular attention to connectors, which may be detached or corroded.
Check the accelerator position sensors
=> Page
24-144

Check the voltage supply to the throttle valve control unit.

Unplug the connector from the throttle valve control unit.
Switch on the ignition.

Connect hand-held multimeter (voltage range) between the following contacts on the connector:

Connector / Contact · Specified value
2 + earth · approx. 5 V.
2 + 6 · approx. 5 V.

If the specified values are attained:

Additionally check signal wires and actuation lines of throttle valve positioner
=> Page
24-143
.

If the specified values are not attained:

Check wiring between engine control unit and throttle valve control unit
=> Page
24-143
.

Checking wiring

Disconnect the connector from the throttle valve control unit.
Connect the V.A.G 1598/31 test box to wiring harness leading to engine control unit; engine control unit should not be connected => Page
24-20
.
Check for open circuit and short to earth/positive or earth in the following wiring connections:

Connector / Contact · Test box V.A.G 1598/31 / Bush
1 · 92
2 · 83
3 · 117
4 · 84
5 · 118
6 · 91

Rectify any open/short as necessary.

If no wiring fault is detected:

Replace throttle valve control unit