P0117

DTC P0117 or P0118

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

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

DTC P0118
- Engine Coolant Temperature (ECT) Sensor Circuit High Voltage

Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT sensor signal circuit and supplies a ground for the low reference circuit.

Conditions for Running the DTC

P0117
* The engine run time is more than 3 seconds.
OR
The ignition is ON and the IAT parameter is less than 90°C (194°F).
* The diagnostic runs continuously when the above condition is met.

P0118
* The engine is running for more than 30 seconds.
OR
The ignition is ON and the IAT parameter is more than 0°C (32°F).
* The diagnostic runs continuously when the above condition is met.

Conditions for Setting the DTC

P0117

The control module detects that the ECT sensor parameter is more than 139°C (282°F) for more than 24 seconds.

P0118

The control module detects that the ECT sensor parameter is less than -37°C (-35°F) for more than 24 seconds.

Action Taken When the DTC Sets

DTCs P0117 and P0118 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0117 and P0118 are Type B DTCs.

Circuit/System Verification

1. Ignition ON, observe the ECT Sensor parameter. The reading should be between +139 to -37°C (+282 to -35°F).
2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the ECT sensor.
2. Ignition OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal 2 and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, verify the scan tool ECT parameter is less than -39°C (-38°F).

• If greater than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the ECM.

4. Install a 3A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECT parameter is greater than 149°C (300°F).

• If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the ECT sensor.

Component Testing

Measure and record the resistance of the ECT sensor at various ambient temperatures, then compare those measurements to the Temperature vs Resistance table. Refer to Temperature Versus Resistance.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Engine Coolant Temperature Sensor Replacement
* Control Module References for ECM replacement, setup, and programming Verification Tests