| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
The ECM determines ignition timing and outputs ignition signals (IGT) for each cylinder. Based on IGT signals, the ignitor controls the primary ignition signals (IGC) for all ignition coils. The ignitor also sends an ignition confirmation signal (IGF) as a fail-safe measure to the ECM. DTC is set when there is no IGF signal to ECM for 6 consecutive IGT signals during engine operation. Possible causes are
- IGF or IGT open or short circuit from ignitor to ECM.
- Ignitor.
- ECM.
Note. For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.