P0118

DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High 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, the sensor resistance becomes less and the voltage drops. The voltage measured across the thermister is interpreted as a temperature. This is a type B DTC.

Conditions for Setting the DTC

^ Engine running for at least 8 minutes.
^ ECT less than -30°C (-22°F).
^ Conditions met for 2 seconds

Action Taken When the DTC Sets

Idle increase

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 (160°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 ECT temperature should rise steady to about 85°C (185°F). A mis-scaled sensor could result in poor driveability complaints.

Test Description

Number(s) below refer to number(s) on the diagnostic tables.

2. This test determines if P0118 is an intermittent condition.

3. This test will determine if signal circuit is open, or a faulty PCM.