Note: The test is performed on a warm engine.
Disconnect the idle speed control valve connector and connect a voltmeter to the connector terminals (see fig.).
Turn on the ignition, make sure that the voltmeter shows the battery voltage and turn off the ignition.
Connect the valve connector, turn on the ignition and check by touch for vibration when the valve is operating. If no vibration is felt after turning on the battery voltage, replace the valve.
Possible malfunctions of the K-Jetronic injection system, their causes and methods of elimination (see table).
Determination of faults in the K-Jetronic injection system and their elimination must be performed with normal compression in the cylinders, with adjusted gaps in the valve timing mechanism, with the ignition timing set correctly, with serviceable electrical equipment, with a clean and serviceable air filter.
(This article was previously published on the resource: AudiManual)