| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuits are okay. If either are defective, 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 - IMPORT article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. |
Circuit Description
ECM determines ignition timing and outputs ignition signals (IGT) for each cylinder. Based on IGT signals, ignitor controls the primary ignition signals for all ignition coils. 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. If DTC P1305 exists, ECM will operate in fail-safe mode. Possible causes are
- IGF or IGT2 circuit from ignitor to ECM is open or shorted.
- Defective ignitor/ignition coil.
- Defective ECM.
Diagnostic Aids
Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.