P0603 MERCEDES-BENZ – Internal Control Module Keep Alive Memory Error

P0603 MERCEDES-BENZ Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light),Engine may not start

P0603 MERCEDES-BENZ Possible Causes

Loose or poor battery terminal connection,Low battery charge,ECM power supply circuit is open or shorted,ECM Programing,Faulty ECM

P0603 MERCEDES-BENZ Description

Battery voltage is supplied to the ECM even when the ignition switch is turned OFF for the ECM memory function of the DTC memory, the air-fuel ratio feedback compensation value memory, the idle air volume learning value memory, etc.