SAAB WIS ONLINE

Throttle position information sent to theTCS and AF22 control modules

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 TCS control module.

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 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 wiring.


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, see .

4. If the throttle position sensor is OK and the signal from pin 54 is absent or not OK, turn to for further diagnostic instructions.