| WARNING | Read service precautions before proceeding with service procedure. See SERVICE PRECAUTIONS . |
| CAUTION | If Engine Control Module (ECM) replacement is instructed in following test, always ensure ECM electrical connectors and ground circuits are okay. If either are defective, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
The Hybrid Vehicle Electronic Control Unit (HV ECU) communicates with the ECM over the ESTP circuit. DTC is set when communication between HV ECU and ECM is interrupted for 2 seconds or more. Possible causes are
- Defective wiring or electrical connectors.
- Defective HV ECU.
- Defective ECM.
