P0117

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is a thermistor that controls signal voltage to the PCM. When the engine is cold, the sensor resistance is high, therefore the PCM will see a high signal voltage. As the engine warms, the sensor resistance becomes less and the voltage drops. The voltage measured across the thermistor is interpreted as a temperature. This is a type B DTC.

CONDITIONS FOR SETTING THE DTC
The engine coolant temperature is greater than or equal to 151°C (304°F) for 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ High idle.
^ No TCC.
^ Shirt schedules will be affected.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the Malfunction Indicator Lamp (MIL) off after three consecutive trips without a fault condition.
^ A History DTC will clear after forty consecutive warm-up cycles during which the diagnostic does not fail (the coolant temperature has risen 5°C (40°F) from the start up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle).
^ Use of a Scan Tool will clear DTC codes.

DIAGNOSTIC AIDS
Check the harness routing for a potential short to ground. After the engine has started, the ECT temperature should rise steady to about 85°C (185°F). A mis-scaled sensor could result in poor driveability complaints. Refer to Temperature vs Resistance. Specifications

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. If the fault is still present, the engine coolant voltage will greater than 151°C (303°F).
3. This test simulates a DTC P0117. If the PCM recognizes the high signal voltage (low temperature) the PCM and the wiring are okay.