IF YOU CONFIRM The MIL is "ON" with DTC P0603 (ECM BACK UP/CIRCUIT). ACTION 1. Confirm that the battery voltage is 11 volts, or more, with the ignition ON (engine OFF, not running). 2. Erase DTC 3. Perform DTC confirmation steps in the Service Procedure. 4. Confirm 1st trip DTC P0603 is not stored. NOTE: P0603 is often the result of low battery voltage, discharged battery or battery terminal disconnections. Please see this bulletin for furtner details.
