P0603 – Internal Control Module Keep Alive Memory Error

P0603 Possible Symptoms

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

P0603 Possible Causes

Loose or poor battery terminal connection,Low battery charge,Engine Control Module (ECM) / Powertrain Control Module (PCM) power supply circuit is open or shorted,ECM/PCM Programing,Faulty ECM/PCM

P0603 Description

Battery voltage is supplied to the Engine Control Module (ECM) / Powertrain Control Module (PCM) even when the ignition switch is turned OFF for the ECM/PCM memory function of the DTC memory, the air-fuel ratio feedback compensation value memory, the idle air volume learning value memory, etc.