P0116
DTC P0116
DTC Descriptor
DTC P0116
- Engine Coolant Temperature (ECT) Sensor Performance
Diagnostic Fault Information
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
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 volts to the ECT sensor 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 timer is met at start-up, the ECM will compare the temperature difference between the ECT and the intake air temperature (IAT) sensor to determine if the temperatures are within an acceptable operating range of each other.
Conditions for Running the DTC
* DTCs P0112, P0113, P0117, P0118, P0601, P0602, P0603, P0604, P0606, P0607, P062F, P2610 are not set.
* The ignition is ON.
* The IAT parameter is more than 15°C (59°F).
* The Fuel Level Sensor parameter is more than 10 percent.
* The vehicle has a minimum ignition OFF time of 8 hours.
* This diagnostic runs once per ignition cycle when the above conditions are met.
Conditions for Setting the DTC
* The control module detects a temperature difference between the ECT sensor and the IAT sensor of more than 100°C (180°F) at start- up.
OR
* The control module detects a temperature difference between the ECT sensor and the IAT sensor of more than 15°C (27°F) and the time elapsed cranking the engine without starting is more than 5 seconds.
OR
* The control module detects a temperature difference between the ECT sensor and the IAT sensor of more than 15°C (27°F). The vehicle must then be driven for 5 minutes over 40 km/h (25 mph). If the IAT sensor temperature decreases more than 5°C (9°F), an engine block heater was detected and the test is aborted. If the IAT sensor temperature 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 DTC
DTC P0116 is a Type B DTC.
Circuit/System Verification
Caution: 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.
1. Turn OFF the ignition.
2. Inspect the cooling system surge tank for the proper coolant level.
3. If the ignition has been OFF for 8 hours or more, the ECT and the IAT should be within 15°C (27°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.
4. Use the scan tool to verify the proper operation of the engine cooling system fans.
Important: A critical analysis of the operation of the thermostat is necessary to properly diagnose these DTCs.
5. Verify the proper heat range and the operation of the thermostat. Refer to Thermostat Diagnosis. Component Tests and General Diagnostics
Circuit/System Testing
Important: All electrical components and accessories must be turned OFF and allowed to power down.
1. Ignition OFF, disconnect the harness connector at the ECT sensor.
2. Ignition OFF, test for less than 5 ohms of resistance 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 ECM.
3. Ignition ON, verify the scan tool ECT parameter is less than -39°C (-38°F).
^ If greater than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the ECM.
4. Install a 3A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool ECT parameter is greater than 149°C (300°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 ECM.
5. If all circuits test normal, test or replace the ECT sensor.
Component Testing
Measure and record the resistance of the ECT sensor at various ambient temperatures, then compare those measurements to the Temperature vs Resistance table. Refer to Temperature Versus Resistance.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Engine Coolant Temperature Sensor Replacement
* Refer to Programming and Relearning. Programming and Relearning