P0603 Buick ECM Power Supply Circuit
Possible causes
– Loose or poor battery terminal connection
– Low battery charge
– ECM power supply circuit is open or shorted
– ECM Programing
– Faulty ECM
– Low battery charge
– ECM power supply circuit is open or shorted
– ECM Programing
– Faulty ECM
Tech description
Start by charging the vehicles battery and clean terminal, once the battery is charged and the terminals are clean and secure, erase code. If the code comes back ON you may have to reprogram or replaced ECM
What about the obd code?
Indicates the ECM has experienced an internal memory fault.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Engine may not start
– Engine may not start
P0603 Buick 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.
Buick Vehicle:Buick Regal – ?Buick Riviera – ?Buick LaCrosse – ?David Dunbar Buick – Buick Century – Buick LaCrosse – Buick LeSabre – Buick Lucerne – Buick Park Avenue – Buick Regal – Buick Verano – Buick Enclave – Buick Encore – Buick Rainier – Buick Rendezvous – Buick Terraza – Buick Riviera