Lambda Sensor

The arrow points to the plug connection of the lambda sensor.

This test requires a CO meter, so a workshop visit may be necessary. For a correct check, the exhaust system must be in good condition and the lambda sensor must receive power (are the fuses good?).

PROCEDURE

Warm up the engine.

Connect the CO meter.

Start the engine and let it run at idle for at least 2 minutes.

Increase engine speed to 2000 rpm.

Record the CO content.

On the throttle body, disconnect the vacuum hose from the fuel pressure regulator and close the tube with a finger.

The CO content should briefly increase and then drop back to the previously measured value.

If the CO value does not change, disconnect the lambda sensor plug connector.

Using a wire, connect the contact on the plug (to the control unit) in turn to the positive and negative battery terminals.

If the CO reading changes during this test, the lambda sensor is faulty.

If the CO content remains unchanged, check the wiring to the control unit.

If there are no faults here, the control unit is faulty.