P1211,P1212
Symptom: Idle uneven, slow or fast
Idle air control valve (IAC), 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 the circuit to pin
4.
1.
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Activate the ISAT commands
"CALC. AIR MASS" and "ACTUAL AIR
MASS" in the "READ FUNCTIONS" menu or activate the ISAT command
"IAC VALVE" in the "ACTIVATE" menu and listen to check whether
the valve is working. (0.5 Hz).
If it is, proceed to point 3.
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2.
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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 17 for continuity/shorting.
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3.
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Measure the resistance across pins 1 and 2 of the valve.
The resistance should be 6-10 ohms. If it is not, change the IAC valve.
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4.
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Start the engine and check the voltage across pins 1 and 2 of the
connector.
With the engine running at idling speed, the voltage
across pins 1 and 2 should be about 5-7 V. (The frequency should be 100
Hz.)
If correct readings are obtained, check the valve
manually for binding. If the valve is OK, proceed to point 6.
If incorrect readings are obtained, continue as
described below.
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5.
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Check the lead between pin 1 of the IAC valve and pin 4 of the MOTRONIC
control module for continuity/shorting.
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6.
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Clear all the trouble codes and drive the car on the road to check
whether any codes are generated afresh. If they are, turn to
for
further diagnostic instructions.
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