Idle Speed Stabilization

PROCEDURE

Switch the ignition on; the valve should make a slight humming sound. You may also feel a slight vibration.

If not, check the fuses.

If all fuses are good, disconnect the idle speed control valve connector. Using a diode test lamp, check for power at the connector on the black-blue wire contact (with the ignition on). To do this, connect the other terminal of the test lamp to ground.

If the lamp lights, the valve has power. Next, check the valve itself:
Connect an ohmmeter and measure the resistance at the valve's plug contacts.

If the valve is good, the resistance should be 2–10 Ω.

If the specified value is not achieved, replace the valve.

If the resistance is correct, the cause of the fault should be sought in a wiring break or a defect in the Digifant injection control unit.

To check the control, the control current is measured. For this, the workshop uses the V.A.G 1551 fault code reader; measurement with improvised means makes no sense.