DTC Advanced Diagnostics: P0117, P0118
DTC P0117:Engine Coolant Temperature (ECT) Sensor 1 Circuit Low Voltage
DTC P0118:Engine Coolant Temperature (ECT) Sensor 1 Circuit High 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. ECT sensor 1 resistance varies depending on the engine coolant temperature. As the engine coolant cools, ECT sensor 1 resistance increases, and the powertrain control module (PCM) detects a high signal voltage. As the engine coolant warms, 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
Execution
Continuous
Sequence
None
Duration
2 seconds or more
DTC Type
One drive cycle, MIL on

Enable Conditions
Condition
 
Vehicle
ON mode

Malfunction Threshold
DTC: P0117

The ECT sensor 1 output voltage [ECT SENSOR 1] is 0.08 V or less for at least 2 seconds.

DTC: P0118

The ECT sensor 1 output voltage [ECT SENSOR 1] is 4.92 V or more for at least 2 seconds.

[ ]: HDS Parameter

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
DTC: P0117
ECT sensor 1 TW line short to ground

DTC: P0118
ECT sensor 1 TW line open
ECT sensor 1 SG line open

Common
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 12 volt battery.