P0603 MAZDA – ECM malfunction

P0603 MAZDA Possible Symptoms

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

P0603 MAZDA Possible Causes

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

P0603 MAZDA 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.