| 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
The ECT sensor is a thermistor that monitors coolant temperature. If DTC P0115 is set, ECM will operate in fail-safe mode (engine coolant temperature is fixed at 176°F (80°C)). DTC is set when ECM detects a open or short in the ECT circuit. Possible causes are
- ECT sensor open or short circuit.
- ECT sensor.
- ECM.
Note. If DTCs P0110, P0115, P0120, P0450 and P1120 are output together, inspect ECM terminal E2 (ground) circuit for an open. Repair as necessary. See appropriate wiring diagram in SYSTEM WIRING DIAGRAMS article.