P1212

DIAGNOSTIC TROUBLE CODES P1211, P1212
Idle Air Control (IAC) valve, output from control module low/high,
No continuity or shorting to ground/batt+.

Fault Symptom.
Idle uneven, slow or fast.

Condition
No continuity or shorting to ground/batt+ in one of the circuits to pin 4 or pin 22.

Diagnostic Procedure.
1. Activate the ISAT command "IAC VALVE" in the "ACTIVATE" menu and listen to check whether the valve is working (1 Hz).

If it is, proceed to step 3.

2. With the ignition switch in the DRIVE position, unplug the IAC valve connector and check whether current is present on pin 2 of the IAC valve.

If it is not, check the lead between pin 2 of the valve and fuse 16B for continuity/shorting.

3. Measure the resistance across pins 1 and 2 of the valve and also across pins 2 and 3.
The resistance should be 9-15 ohms.

If it is not, change the IAC valve.





4. With the ignition switched OFF and all current consuming equipment disconnected, measure the resistance across pin 1 and a good grounding point on the engine and also across pin 3 and a good grounding point on the engine.
The resistance should be 2-30 kOhms.

If correct readings are obtained, proceed to step 6.
If incorrect readings are obtained, continue as described below.

5. Check the leads between pin 1 of the IAC valve and pin 22 of the MOTRONIC control module, and also between pin 3 of the IAC valve and pin 4 of the MOTRONIC control module, for continuity/shorting.

6. Clear all the trouble codes and drive the car on the road to check whether any codes are generated afresh.

If they are, conmtinue at "Before Control Module Replacement" for further diagnostic instructions. Before Replacing A Control Module