P0117

DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage






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 high signal voltage. As the engine warms, sensor resistance becomes less and voltage drops. The voltage measured across the thermistor is interpreted as a temperature. This is a type B DTC.

Conditions for Setting the DTC

Engine coolant temperature greater than or equal to 151°C (303°F) for 2 seconds.

Action Taken When the DTC Sets

^ High idle
^ No TCC
^ Shift schedules will be affected.

Conditions for Clearing the MIL/DTC

^ The PCM will turn the MIL off after three consecutive trips without a fault condition.
^ A History DTC will clear when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (16O°F) that same ignition cycle).
^ Use of a Scan Tool.

Diagnostic Aids

Check harness routing for a potential short to ground. After engine is started, the coolant temperature should rise steadily to about 85°C (185°F). refer to "Intermittents" on page 14. A "skewed" sensor could result in poor driveability complaints.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

2. This step determines if PO117 is a hard failure or an intermittent condition.

3. This test will check the PCM and the wiring.