Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
DTC Descriptor
DTC P0116: Engine Coolant Temperature (ECT) Sensor PerformanceDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
ECT Sensor Signal | P0117, P0119 | P0118, P0119 | P0118¹, P0119¹ | P0116 |
Low Reference | -- | P0118, P0119 | P0118¹, P0119¹ | P0116 |
¹ Internal ECM or ECT sensor damage may occur if the circuit is shorted to B+. | ||||
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: Varies with ambient temperature and engine operation. | |||
ECT Sensor Signal | 0 Volts | 5 Volts | 5 Volts¹ |
Low Reference | -- | 5 Volts | 5 Volts¹ |
¹ Internal ECM or ECT sensor damage may occur if the circuit is shorted to B+. | |||
Circuit 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 signal circuit and supplies a ground to the low reference circuit. The ECM monitors the mutual performance of the ECT and the intake air temperature (IAT) signals. The ECM monitors the warm up and cool down behavior of the sensors. After a vehicle has been driven at operating temperature is shut down, a decrease in the ECT is expected, over a period of time.
The following table illustrates the difference between temperature, resistance, and voltage:
Temperature | ECT Resistance | ECT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
Conditions for Running the DTC
Condition 1
| • | The engine off timer is greater than 60 minutes. |
| • | The engine run time is less than 5 minutes. |
| • | The IAT at startup is between 10-50°C (50-122°F). |
| • | The difference between ambient air temperature and the IAT is greater than 15°C (27°F). |
| • | DTC P0116 runs once an ignition cycle when the above conditions are met. |
Condition 2
| • | The engine is running. |
| • | The ignition voltage is greater than 10 volts. |
| • | The ECT at startup is less than 76°C (169°F). |
| • | DTC P0116 runs once an ignition cycle when the above conditions are met. |
Condition 3
| • | The engine is running. |
| • | The ignition voltage is between 10-26 volts. |
| • | The ECT at startup is greater than 76°C (168°F). |
| • | The IAT at startup is between 10-70°C (50-158°F). |
| • | The ambient air temperature is greater than -10°C (14°F). |
| • | DTC P0116 runs once an ignition cycle when the above conditions are met. |
Conditions for Setting the DTC
The ECM detects that the ECT does not change a calibrated amount, in a calibrated amount of time.
Action Taken When the DTC Sets
DTC P0116 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0116 is a Type B DTC.
Diagnostic Aids
| • | If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (6°F). |
| • | After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens. |
| • | A short to ground or voltage through a conductive material or fluid could set this DTC. Inspect the ECT sensor for evidence of coolant leaking into the connector body. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Circuit/System Verification
- Inspect the engine coolant level. Verify the cooling system is operating correctly.
- Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
| ⇒ | If the cooling system is not operating correctly, refer to Symptoms - Engine Cooling . |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the ECT sensor.
- Ignition OFF for at least 20 seconds, test for less than 5 ohms of resistance between the low reference circuit and ground.
- Verify the scan tool ECT sensor voltage parameter is at 5 volts.
- Install a 3-A fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool ECT sensor voltage parameter is less than 1 volt.
- If all circuits test normal, test or replace the ECT sensor.
Important: The control module or the sensor may be damaged if the circuit is shorted to battery positive voltage.
| ⇒ | If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance . If the circuit tests normal, replace the ECM. |
| ⇒ | If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | 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. |
Component Testing
- Ignition OFF, disconnect the harness connector at the ECT sensor.
- Test the sensor by varying the sensor temperature while monitoring the sensor resistance.
- Compare the readings with the Temperature Versus Resistance table and verify that the resistance is within 5 percent of the specification.
Important: A thermometer can be used to test the sensor off the vehicle.
| ⇒ | If not within the specified range, replace the ECT sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming |
