| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. |
Circuit Description
Battery voltage is supplied to BATT terminal at ECM at all times. This circuit is used by diagnostic trouble code memory and air/fuel ratio adaptive control value memory. DTC is set if there is an open in back-up power source circuit. Possible causes are
- Open in back-up power source circuit.
- Faulty ECM.
Diagnostic Aids
Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.