Checking throttle valve drive angle senders 1 and 2 -G187 and -G188 — AUDI

The throttle valve drive angle senders 1 and 2 -G187 and -G188 provide the engine control unit with information on the position of the throttle valve. Both angle senders are located in the throttle valve control part.

Connect vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select engine electronics control unit with "address word" 01 => Page
01-8
.

Rapid data transfer
HELP
Select function XX
Indicated on display:

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

Read measured value block
Q
Enter display group number
XXX
Indicated on display:

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

Read measured value block 62
⇒
1
2
3
4
Indicated on display:

Check specifications for electronic throttle system potentiometer voltages.

Display zones
1 · 2 · 3 · 4
Display group 62: Electronic throttle system potentiometer voltages with ignition on
Display · xx % · xx % · xx % · xx %
Readout · Throttle valve angle / (angle sender 1) · Throttle valve angle / (angle sender 2) · Accelerator pedal position / sender · Accelerator pedal position / sender 2
Operating range · min.: 0 % / max.: 100 % · min.: 0 % / max.: 100 % · min.: 0 % / max.: 100 % · min.: 0 % / max.: 100 %
Specification · 3...93 % · 97...3 % · 12...97 % · 4...94 %

Note:

The engine control unit converts the angle sender voltage values into percentages referenced to 5 V and displays the percentage values (5 V supply voltage corresponds to 100 %).

Observe display zones 1 and 2.
Slowly floor accelerator pedal.

The percentage value displayed in zone 1 must increase steadily. The tolerance range 3...93 % is not fully utilised.

The percentage value displayed in zone 2 must decrease steadily. The tolerance range 97...3 % is not fully utilised.

If displays are not as described:

Check power supply and wiring of throttle valve control part =>Page
24-164
. Pay particular attention to the possibility of connectors being unplugged or corroded.
Check accelerator pedal position senders =>Page
24-171
.

Notes:

The reason for the display in zone 1 increasing, whereas the display in zone 2 decreases, is that the potentiometers (angle senders) in the throttle valve control part operate in opposite directions.
In other words, the voltage tap value of angle sender 1 moves towards 5 V (the further the throttle valve is opened, the greater the voltage becomes; the percentage reading increases).
The voltage tap value of angle sender 2 moves away from 5 V towards 0 V (the further the throttle valve is opened, the lower the voltage becomes; the percentage reading decreases).

Checking power supply of throttle valve control part

Unplug connector of throttle valve control part.
Switch on ignition.
Connect portable multimeter for voltage measurement to the following connector sockets:

6-pin connector at wiring harness, socket · Specification
2 + earth · approx. 5 V
2 + 6 · approx. 5 V

If readings do not match specifications, check wiring between engine control unit and throttle valve control part => Page
24-164
.

If readings match specifications, additionally check signal wires and actuation wires of throttle valve actuator => Page
24-164
.

Checking power, signal and actuation wiring

Unplug connector of throttle valve control part.

Connect test box V.A.G 1598/31 to engine control unit wiring harness. Actual engine control unit is not to be connected=>Page
24-12
.

Check for short to positive/earth and open circuit in the following wiring.

6-pin connector at wiring harness, socket · Test box V.A.G 1598/31, socket
1 · 92
2 · 83
3 · 117
4 · 84
5 · 118
6 · 91

Resistance: max. 1.5 ohms

If necessary, eliminate open circuit in wiring/short circuit.

=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations binder

If no fault is found in wiring:

Replace throttle valve control part.