Drive Input

DRIVE INPUT (AUTOMATIC TRANSMISSION)
1. Start the engine and check whether any significant momentary drop in idling speed occurs when shifting from P or N to 1, 2, 3, D or R.

If it does, check that voltage is present on pin 47 of the MOTRONIC control module when R, D, 3, 2 or 1 is selected.
If voltage is present, proceed to step 3.
If it is not, continue as described below.

2. Check the operation of the automatic transmission.
Also check the lead between pin 11 of the automatic transmission and pin 47 of the MOTRONIC control module for continuity/shorting.





3. With the ignition switched OFF, connect a BOB to the MOTRONIC control module.
Start the engine and check whether the voltage across pins 4 and 37 increases by about 0.5-1.0 V when any gear is selected.

If the voltage increases but engine idling speed drops momentarily, proceed to step 4.
If the voltage does not increase, proceed to step 5.

4. Check that pin 2 of the Idle Air Control (IAC) valve is supplied with battery voltage.

Also check the lead between pin 4 of the control module and pin 3 of the IAC valve, and the lead between pin 22 of the control module and pin 1 of the AC valve, for continuity/shorting.

Also check the mechanical operation of the AC valve for binding, through-flow, etc.

5. If, after the above tests have been carried out, a momentary drop in idling speed still occurs when any gear is selected, continue at "Before Control Module Replacement" for further diagnostic instructions. Before Replacing A Control Module