Symptoms – Engine Light ON (or Service Engine Soon Warning Light)

Possible causes – Faulty Heated Oxygen Sensor– Heated Oxygen Sensor harness is open or shorted– Heated Oxygen Sensor circuit poor electrical connection Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P1031 MERCEDES-BENZ Description Heated Oxygen Sensor (HO2S)

Possible causes – The EGR volume control valve circuit harness is open or shorted– EGR volume control valve leaking or stuck open– Faulty EGR temperature sensor Tech notes Start by cleaning the EGR valve, if the code persist it may