Throttle Position

THROTTLE POSITION INFORMATION SENT TO THE TCS AND AF22 CONTROL MODULES

Fault Symptom.
Diagnostic trouble code P1785 generated in the AF22 control module or one of the diagnostic trouble codes P1406, P1407 or P1408 generated in the Traction Control System (TCS) control module.

Diagnostic Procedure.
1. Use the ISAT command "THROTTLE POSITION" in the "READ FUNCTIONS" menu and, with the ignition switch in the DRIVE position, check whether the ISAT shows about 9% in the idling position and steadily increases to 85-90% in the full throttle position.

2. With the ignition switched OFF, connect a BOB between the MOTRONIC control module and the cable.

With the warmed-up engine switched OFF and the ignition switch in the DRIVE position, check that a 100 Hz PWM signal of 0.25-1.0 V is present on pin 54.

Start the engine and check that the voltage applied to pin 54 is:
- about 1.2 V at idling speed,
- about 2.0 V at 2500 rpm,
- about 12 V at full throttle.

3. If the signal is absent or not OK, check the throttle position sensor, continue at "DTC P0122 and P0123" at "Diagnostic Charts/DTC Charts". P0123

4. If the throttle position sensor is OK and the signal from pin 54 is absent or not OK, continue at "Before Replacing Control Module" for further diagnostic instructions. Before Replacing A Control Module