DTC P0117
DTC P0117: Engine Coolant Temperature (ECT) Sensor 1 Circuit Low Voltage
General Description
Engine coolant temperature (ECT) sensor 1 is used for air/fuel ratio feedback control, ignition timing control, idle speed control, and other functions. The ECT sensor 1 resistance varies depending on the engine coolant temperature. As the engine coolant cools, the ECT sensor 1 resistance increases, and the powertrain control module (PCM) detects a high signal voltage. As the engine coolant warms, the ECT sensor 1 resistance decreases, and the PCM detects a low signal voltage. If the ECT sensor 1 output voltage is a set value, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type, OBD Status
| Execution | Continuous |
| Sequence | None |
| Duration | 2 seconds or more |
| DTC Type | One drive cycle, MIL on |
| OBD Status | PASSED/FAILED/NOT COMPLETED (STILL TESTING) |
Enable Conditions
| Condition | |
|---|---|
| Ignition switch or Engine start/stop button | Vehicle ON mode |
| No active DTCs set (prevents monitor from running) | P0118 |
Malfunction Threshold
The ECT sensor 1 output voltage [ECT SENSOR 1] is 0.08 V or less for at least 2 seconds.
[ ]: HDS Parameter
Possible Cause
- ECT sensor 1 TW line short to ground
- ECT sensor 1 failure
- PCM internal circuit failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.
Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.