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 signal circuit and supplies a ground to the low reference circuit.
The ECM uses this high side coolant rationality diagnostic 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 ignition is OFF. If the calibrated ignition OFF time is met at start-up, the ECM will compare the temperature difference between the ECT and the intake air temperature (IAT), to determine if the temperatures are within an acceptable operating range of each other.
Conditions for Running the DTC
* DTCs P0112, P0113, P0117, P0118, P0502, P0503, P0601, P0603, P062F, P2610 are not set.
* The vehicle has had a minimum ignition OFF time of 10 h.
* The ignition is ON.
* The start-up IAT is greater than -7°C (+19°F)
* The Fuel Level Sensor parameter is greater than 5%.
* This DTC runs once per ignition cycle when the above conditions are met.
Conditions for Setting the DTC
* The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 30°C (54°F) greater than the IAT sensor.
OR
* The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 10°C (18°F) greater than the IAT sensor, and the time spent cranking the engine is greater than 10 s, when the fuel level is greater than 5%.
OR
* With the power-up IAT greater than -7°C (+19°F), the ECM detects a temperature difference at power-up that indicates that the ECT sensor is 20°C (36°F) greater than the IAT sensor. Then the vehicle must be driven for greater than 6 min and 40 s at greater than 40 km/h (25 mph). If the IAT sensor then decreases greater than 4°C (7°F), an engine block heater was detected and the test is aborted. If the IAT sensor does not decrease, an engine block heater was not detected and DTC P0116 will set.
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.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
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 (Programming and Relearning) for scan tool information
Circuit/System Verification
1. If the ignition has been OFF for 8 h or more, the ECT and the IAT, should be within 6°C (11°F) of each other and also the ambient temperature. Turn ON the ignition, with the engine OFF, and use a scan tool to observe the IAT and the ECT sensor parameters. Compare those sensor parameters to each other and also to the ambient temperature. A slight to moderate resistance in the IAT signal or low reference circuit, can widen the spread between the two sensors and cause this DTC to set.
2. An IAT sensor that is skewed lower at various ambient temperatures, due to more resistance than is normal, can widen the spread between the two sensors and cause this DTC to set. Measure and record the resistance of the IAT sensor at various ambient temperatures, and then compare those measurements to the Temperature vs Resistance Table. Refer to Temperature Versus Resistance (Temperature Versus Resistance).
3. Inspect the ECT sensor terminals for corrosion, and for engine coolant leaking through the sensor.
Warning
Under pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders, and the person removing the cap. Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use at any time. Flammable antifreeze could cause a serious fire.
4. Turn OFF the ignition.
5. Inspect the cooling system surge tank for the proper engine coolant level. Refer to Cooling System Leak Testing (Component Tests and General Diagnostics) and Cooling System Draining and Filling (LS3, L99 Static Fill) (Cooling System Draining and Filling (Static Fill))Cooling System Draining and Filling (LLT Static Fill) (Cooling System Draining and Filling (Static Fill))Cooling System Draining and Filling (GE 47716) (Cooling System Draining and Filling (GE 47716)).
Circuit/System Testing
Note: All electrical components and accessories must be turned OFF and allowed to power down.
1. Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
2. Ignition OFF, test for less than 5 ohm between the low reference circuit terminal A 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 ECM.
3. Ignition ON, 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 B for a short to ground. If the circuit tests normal, replace the K20 ECM.
4. Install a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool ECT Sensor parameter is greater than 149°C (300°F).
• If less than the specified range, test the signal circuit terminal B for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
5. If all circuits test normal, test or replace the B34 ECT sensor.
Component Testing
Measure and record the resistance of the B34 ECT sensor at various ambient temperatures, then compare those measurements to the Temperature vs Resistance Table. Refer to Temperature Versus Resistance (Temperature Versus Resistance).
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 (Programming and Relearning) for ECM replacement, setup, and programming