| 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. |
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.
- ECM.