Checking the ignition retard control valve (VW Passat B4)

Turn on the ignition. Open and close the throttle valve. You should hear a click twice in valve 1 (Fig. 2-58) of the ignition delay control. If there are no clicks, disconnect the idle speed controller connector. Connect the tester to the controller block. The LED should light up. Open the throttle valve: the LED should go out.



If the LED goes out and comes on as indicated, replace the valve.

If the LED does not light, check the integrity of the valve circuit. If the circuit is OK, replace the idle speed control stepper motor. If the LED does not go out, replace the idle speed control motor. The valve's functionality can also be checked as follows: turn on the ignition, open and close the throttle valve. You should hear the valve click twice; if there are clicks, start the engine at idle speed, disconnect the connector 2 valve, then reconnect it. In this case, the crankshaft speed at idle speed should increase, then decrease, which indicates the correct setting of the ignition timing angle; if the above conditions are not met, replace the valve with a new one.