Idling speed too fast
Read the instructions below then
start the fault diagnostic procedure.
Symptom: Idling speed too fast
Fault symptoms
Idling speed too fast
Conditions
The following conditions apply for this fault symptom:
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No diagnostic trouble codes in the car with the symptom description in question.
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Note
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Idling speed is always higher with a cold engine and for a short period after starting.
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Diagnostic help
First check that the pedal arm returns completely. Then check that the throttle body is not in limp-home mode without this being detected by the control module. This may happen if a fault has occurred in the throttle and the diagnostic trouble codes are cleared, or if the current supplied to the control module is cut off without the mechanism having been reset. After that, check for air leaks after the throttle valve. The additive fuel adaptation generally exceeds 4 mg/c in the event of such a fault. A considerable negative adaptation generally indicates that the EVAP canister purge valve has stuck in the open position.
Diagnostic tool functions related to this fault are:
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Idle speed control, ON/OFF.
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Idling speed difference, in rpm.
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Additive adaptation, in mg/c.
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See also the description of test values under ”Fault diagnosis, general” for more information.
Check the wiring
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Note
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Jiggle the leads and in-line connectors at various points and in different directions to detect any intermittent breaks or short circuits in the wiring. Observe the multimeter, test lamp or diagnostic tool while doing this.
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