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
^ IAT sensor DTCs are not 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. The temperature would be 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
For intermittent conditions, refer to DTC P1114 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage and/or Symptoms. P1114 Symptom Related Diagnostic Procedures