P0117
DTC P0117 or P0118
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
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 V to the ECT sensor signal circuit and a ground for the low reference circuit.
The purpose of this diagnostic is to determine if the input from the ECT sensor is skewed warmer than normal. The internal clock of the ECM will record the amount of time the engine is OFF. If the required engine OFF time is met at start-up, the ECM will compare the temperature difference between the actual measured ECT and IAT sensors.
Conditions for Running the DTC
P0117
* The ignition is ON.
OR
* The engine is running for greater than 10 s.
* This DTC runs continuously within the enabling conditions.
P0118
* The ignition is ON.
OR
* The engine is running for greater than 10 s.
OR
* The engine run time is less than 10 s when the IAT is warmer than 0°C (32°F).
* This DTC runs continuously within the enabling conditions.
Conditions for Setting the DTC
P0117
The ECM detects that the ECT is warmer than 149°C (300°F) for greater than 5 s.
P0118
The ECM detects that the ECT is colder than -39°C (-38°F) for greater than 5 s.
Action Taken When the DTC Sets
* DTC P0117 or P0118 are a Type B DTC.
* The cooling fans will be commanded ON.
* The Engine Coolant Temperature Gauge is inoperative.
Conditions for Clearing the DTC
DTC P0117 or P0118 are a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool ECT Sensor parameter is between -39 to + 120°C (-38 to +248°F) and changes with engine run time.
• If not between -39 to + 120°C (-38 to +248°F) or does not change
Refer to Circuit/System Testing.
• If between -39 to + 120°C (-38 to +248°F) and changes
3. All OK.
Circuit/System Testing
1. Disconnect the B34 engine coolant temperature sensor harness connector at the sensor.
2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.Test for less than 5 ohms between the low reference circuit terminal A and ground.
• If 5 ohms or greater
1. Ignition OFF, disconnect the harness connector at the K20 engine control module.
2. Test for less than 2 ohms in the low reference circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 engine control module.
• If less than 5 ohms
3. Ignition ON.
4. Verify the scan tool ECT Sensor parameter is colder than -39°C (-38°F).
• If warmer than -39°C (-38°F)
1. Ignition OFF, disconnect the harness connector at the K20 engine control module.
2. Test for infinite resistance between the signal circuit terminal B and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K20 engine control module.
• If colder than -39°C (-38°F)
5. Install a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A.
6. Verify the scan tool ECT sensor parameter is warmer than 149°C (300°F).
• If colder than the 149°C (300°F)
1. Ignition OFF, disconnect the harness connector at the K20 engine control module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Ignition OFF
4. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 engine control module.
• If warmer than 149°C (300°F)
7. Test or replace the B34 engine coolant temperature sensor.
Component Testing
1. Ignition OFF, remove the B34 engine coolant temperature sensor.
2. Test the B34 engine coolant temperature sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance - Engine Coolant Temperature Sensor Temperature Versus Resistance - Engine Coolant Temperature Sensor table and verify that the resistance is within 5% of the specification.
• If not within the specified range
Replace the B34 engine coolant temperature sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Engine Coolant Temperature Sensor Replacement Service and Repair
* Control Module References Control Module References engine control module replacement, programming, and setup.
Repair Verification
1. Ignition ON, observe the ECT Sensor parameter. The reading should be between -39 to + 120°C (-38 to +248°F).
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
3. Verify a DTC does not set.
• If any DTC sets
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
• If no DTC sets
4. All OK