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 00
- 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 P0112 00, P0113 00, P0117 00, P0118 00, and P2610 00 are not set.
* The ignition has been off for greater than 8 h before the engine is started.
* The engine is running.
* 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 00 is a Type B DTC.
Conditions for Clearing the DTC
DTC P0116 00 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)
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. Ignition on, observe the DTC information with a scan tool. Verify that DTC P0112 00, P0113 00, P0117 00, or P0118 00 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 (Static Fill) (Cooling System Draining and Filling (Static Fill))Cooling System Draining and Filling (GE-47716 Fill) (Cooling System Draining and Filling (GE-47716 Fill)).
3. If the ignition has been OFF for 8 h or greater, the B75B Mass Air Flow/Intake Air Temperature Sensor (IAT 1), the B111 Turbocharger Boost Sensor (IAT 2), and the B34A Engine Coolant Temperature Sensor 1 should be within 9°C (16°F) of each other and also the ambient temperature. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2 and the ECT Sensor parameters. Compare those sensor parameters to each other and also to the ambient temperature to determine if the ECT sensor is skewed.
Note: Depending on ambient temperature, it may take up to 4 min for the temperature to equalize.
4. Engine running, observe the ECT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions.
5. 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 data.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the B34A Engine Coolant Temperature Sensor 1.
2. Inspect the B34A Engine Coolant Temperature Sensor 1 terminals for corrosion and for engine coolant leaking through the sensor.
3. Ignition OFF for 1 min, 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. Ignition ON, verify the scan tool ECT Sensor parameter is colder than -39°C (-38°F).
• If greater 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.
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 greater 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 1.
Component Testing
Static Test
1. Ignition off, disconnect the harness connector at the B34A Engine Coolant Temperature Sensor 1.
Note: A thermometer can be used to test the sensor off vehicle.
2. Test the B34A Engine Coolant Temperature Sensor 1 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 B34A Engine Coolant Temperature Sensor 1.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Engine Coolant Temperature Sensor Replacement (Radiator) (Engine Coolant Temperature Sensor Replacement (Radiator))Engine Coolant Temperature Sensor Replacement (Thermostat) (Engine Coolant Temperature Sensor Replacement (Thermostat))Engine Coolant Temperature Sensor Replacement (Water Outlet) (Engine Coolant Temperature Sensor Replacement (Water Outlet))
* Control Module References (Programming and Relearning)for ECM replacement, setup, and programming