P0116
DTC P0116
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 P0116
- Engine Coolant Temperature (ECT) Sensor Performance
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 a calibrated ECT model. The information for this model is derived from the previous drive cycle and includes the accumulated mass air flow (MAF), the engine run time, the ambient air temperature and the ECT at the end of the drive cycle.
If the ECM detects that the temperature difference between the measured and modeled ECT is not within an acceptable operating range of each other, then the ECM will continue to run this diagnostic to determine if a block heater was active during the engine OFF time.
Conditions for Running the DTC
* DTCs P0111, P0112, P0113, P0114, P0117, P0118, and P2610 are not set.
* The ignition has been off for greater than 8 h before the engine is started.
* The engine is running.
* The engine block heater (if equipped) is not detected.
* This DTC runs once per ignition cycle when the above conditions are met.
Conditions for Setting the DTC
The ECM does not detect an ECT sensor change of greater than 10.5°C (50.9°F) within a calibrated time.
Action Taken When the DTC Sets
DTC P0116 is a Type B DTC.
Conditions for Clearing the DTC
DTC P0116 is a Type B DTC.
Diagnostic Aids
* Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor. Engine coolant that is leaking through the sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a warmer ECT.
* An intake air temperature (IAT) sensor that is biased colder at various ambient temperatures due to greater resistance than is normal will increase the range between these 2 sensors. Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to the Temperature vs. Resistance table. Refer to Temperature Versus Resistance Temperature Versus Resistance.
* Test the ECT sensor at various temperature levels in order to evaluate the possibility of a biased sensor. A sensor that is biased warmer can result in a driveability condition. Refer to Temperature Versus Resistance Temperature Versus Resistance.
* A slight to moderate resistance in the IAT sensor signal circuit or low reference circuit will increase the range between these two sensors. This condition results in a greater voltage on the IAT sensor signal circuit, which is interpreted by the ECM as a colder IAT.
* If the condition is intermittent, allow the vehicle to sit for greater then 8 h with the ignition off, may help isolate the condition. Compare the scan tool Radiator Coolant Temperature Sensor and ECT Sensor temperature sensor values at ignition on. The Radiator Coolant Temperature Sensor and the ECT Sensor values should display within 3°C (5°F).
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Connector End Views By Name
Description and Operation
Hybrid Modes of Operation Description Hybrid Modes of Operation Description
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. Service Mode active, observe the DTC information with a scan tool. Verify that DTC P0111, P0112, P0113,O0114, P0117, or P0118 are not set.
• If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
2. Ignition OFF, inspect the cooling system surge tank for the proper coolant level. Refer to Loss of Coolant Loss of Coolant and Cooling System Draining and Filling Cooling System Draining and Filling.
3. Engine idling for 15 minutes with the A/C OFF.
Note: Depending on ambient temperature, it may take up to 4 minutes for the temperatures to equalize.
4. Command the Engine Coolant Thermostat Heater to 100 percent with a scan tool. Increase the engine speed to wide open throttle. Observe the scan tool RCT and the ECT sensor parameters. The RCT and the ECT sensor parameters should be within 20°C (68°F).
5. 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.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the B34A engine coolant temperature sensor.
2. Inspect the B34A Engine Coolant Temperature Sensor terminals for corrosion and for engine coolant leaking through the sensor.
3. Ignition OFF and all vehicle systems OFF. It may take may take up to 2 minutes for all vehicle systems to power down.Test for less than 5 ohm 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 K20 engine control module.
4. Service Mode active, verify the scan tool ECT Sensor parameter is colder than -39°C (-38°F).
• If warmer than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 engine control module.
Note: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECT Sensor parameter is warmer than 130°C (266°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 K20 engine control module.
6. If all circuits test normal, test or replace the B34A engine coolant temperature sensor.
Component Testing
Static Test
1. Ignition off, remove the engine coolant temperature sensor.
Note: A thermometer can be used to test the sensor off vehicle.
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 Temperature Versus Resistance 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 (Water Outlet) Engine Coolant Temperature Sensor Replacement (Water Outlet)Engine Coolant Temperature Sensor Replacement (Thermostat) Engine Coolant Temperature Sensor Replacement (Thermostat)
* Control Module References Control Module References for ECM replacement, setup, and programming