P0117

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is a thermistor, or variable resistor, that measures the temperature of the engine coolant. The PCM supplies 5 volts to the ECT signal circuit through a pull-up resistor. When the engine coolant temperature is cold, the sensor resistance is high. When the engine coolant temperature increases, the sensor resistance lowers. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively low ECT signal voltage (a high temperature indication), DTC P0117 will set.

CONDITIONS FOR RUNNING THE DTC
^ No IAT sensor DTCs are set.
^ The engine has been running for at least 10 seconds.
^ Intake air temperature is less than -70°C (158°F).

CONDITIONS FOR SETTING THE DTC
^ The ECT sensor signal voltage is less than 0.08 volts (approximately 137°C (278°F)).
^ The condition exists for less than 1 second.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.
^ The PCM stores the conditions present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS
Check for a skewed ECT sensor. Refer to Temperature vs Resistance.

If the conditions is intermittent, refer to Intermittent Conditions in Symptoms. Intermittent Conditions