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 provides 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 | P0116¹ |
Low Reference | -- | P0118, P0119 | P0118², P0119² | P0116² |
¹ Sensor damage may occur if the circuit is shorted to B+ ² Internal ECM 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: -39 to +142°C (-38 to +288°F) Varies with coolant temperature. | |||
ECT Sensor Signal | 143°C (289°F) | -40°C (-40°F) | -40°C (-40°F)¹ |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)¹ |
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 driven at operating temperature is shut down. If the ECM detects that the ECT is not with in a predetermined range of IAT after a long soak, or the ECT and IAT are not within a range of each other, as compared to a previous cold start, this DTC sets.
The following table illustrates the difference between temperature, resistance, and voltage:
ECT | ECT Resistance | ECT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
Conditions for Running the DTC
Condition 1
| • | Before the ECM can report DTC P0116 failed, DTC P0101 must run and pass. |
| • | DTCs P0117, P0118, and P0119 are not set. |
| • | The engine run time of the previous ignition cycle was more than 10 minutes. |
| • | The accumulated air mass of the previous ignition cycle was more than 4000 grams. |
| • | The minimum IAT during the previous ignition cycle is between -30 to +2°C (-22 to +36°F). |
| • | The IAT at ignition ON is between -30 to +2°C (-22 to +36°F). |
| • | DTC P0116 runs once an ignition cycle when the above conditions are met. |
Condition 2
| • | Before the ECM can report DTC P0116 failed, DTC P0101 must run and pass. |
| • | DTCs P0117, P0118, and P0119 are not set. |
| • | The ECT at the previous engine shut down is more than 85°C (185°F). |
| • | The ECM detects a predicted rise in the intake air temperature, at ECM power down of the previous ignition cycle. The hood being open or a strong wind may prevent a rise in the IAT from occurring. |
| • | The block heater is not detected. |
| • | DTC P0116 runs once an ignition cycle when the above conditions are met. |
Conditions for Setting the DTC
| • | The ECM determines the difference between the ECT and IAT at ignition ON is not within 10°C (18°F) of the difference recorded during a previous ignition cycle, when the enable conditions were met. |
| OR |
| • | The ECM determines the IAT at ignition ON is within a calibrated range of the ECT and IAT recorded during a previous ignition cycle, but the ECT is not within 10°C (18°F) of the calibrated range. |
| • | Either condition exists for more than 4 seconds. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | Test the ECT and the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a DTC or a driveability condition. Refer to Temperature Versus Resistance - Engine Coolant Temperature Sensor and Temperature Versus Resistance - Intake Air Temperature Sensor . |
| • | If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F). |
| • | After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens. |
| • | High resistance in the circuits of either the ECT or IAT sensor could set a DTC. |
| • | 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. |
| • | The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to Engine Controls Component Views . |
| • | Use the J 35616-A/BT-8637 Connector Test Adapter Kit for any test that requires probing the underhood fuse block terminals, component wire harness terminals, or the ECM wire harness connector terminals. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
- Verify that the following DTCs are not set: P0101, P0117, P0118, P0119.
- Inspect the engine coolant level. Verify that 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 you observed from the Freeze Frame/Failure Records. DTC P0116 should not set.
| ⇒ | If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle . |
| ⇒ | If you suspect a condition with engine cooling system, refer to Symptoms - Engine Cooling . |
Circuit/System Testing
- Ignition OFF, disconnect the ECT sensor.
- Ignition ON, verify that the ECT sensor parameter is at -40°C (-40°F).
- Ignition OFF, remove the ECM/TCM fuse from the underhood fuse block.
- Test for less than 5 ohms between the low reference circuit and the ECM housing.
- Ignition OFF, install the ECM/TCM fuse to the underhood fuse block.
- Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor and verify the ECT sensor parameter is greater than 142°C (288°F).
- If all circuits/connections test normal, test or replace the ECT sensor.
| ⇒ | If greater than -40°C (-40°F), test the signal circuit of the ECT sensor for a short to ground. If the circuit/connections test normal, replace the ECM. |
Notice: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.
Important: The control module or the sensor may be damaged if the circuit is shorted to battery positive voltage.
| ⇒ | If greater than 5 ohms, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit/connections test normal, replace the ECM. |
| ⇒ | If less than 143°C (289°F), test the signal circuit of the ECT sensor for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM. |
Component Testing
- Ignition OFF, disconnect the harness connector of the ECT sensor.
- Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance - Intake Air Temperature Sensor 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 the resistance vs temperature is not within 5 percent, 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 |
