P0116
P0116-ENGINE COOLANT TEMPERATURE SENSOR PERFORMANCE
Theory of Operation
The Powertrain Control Module (PCM) checks the engine coolant temperature sensor signal for 3 fault conditions. One trip fault. Three good trips required to reset the MIL:
Stuck In Range High Voltage: Represented by a fixed cold temperature.
- When Monitored:
The Powertrain Control Module (PCM) monitors the sensor when the temperature is reading below 60° C (140° F).
- Set Condition:
The Powertrain Control Module (PCM) expects the reading to move by at least 3° C during a period of time that the engine has completed 1200 revs. (1 minute 40 seconds at 700 rpm idle). If the temperature does not change then the signal is deemed to be stuck in range.
Stuck In Range Low Voltage: Represented by a fixed hot temperature.
- When Monitored:
The Powertrain Control Module (PCM) monitors the coolant temperature after the engine has been off for more than 5 hours.
- Set Condition:
If the temperature is greater than 60° C (140° F) then the signal is deemed to be stuck in range.
Excessive Rate of Change: Represented by a noisy temperature reading.
- When Monitored:
The Powertrain Control Module (PCM) monitors the coolant temperature whenever the PCM is powered up.
- Set Condition:
If the coolant temperature changes by more than 2° C between readings the signal will be deemed erratic and will lead to a failure.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. DTC IS ACTIVE
NOTE: Diagnose any CAN - C Communication DTCs before continuing.
1. Turn the ignition off.
2. If possible, allow the vehicle to sit with the ignition off for more than 480 minutes in an environment where the temperature is consistent and above -7° C (19.4° F).
3. Test drive the vehicle. The vehicle must exceed 48 km/h (30 mph) during the test drive. Do not cycle the ignition off when the test drive is completed.
4. With a scan tool, select View DTCs.
Is the status Active or Pending for this DTC?
Yes
- Go To 3
No
- Go To 2
2. AMBIENT AIR TEMPERATURE
1. Turn the ignition off.
2. Allow the vehicle to sit with the ignition off in an environment where the temperature is consistent and above -7° C (19.4° F) until the engine coolant temperature is equal to ambient temperature.
3. Turn the ignition on.
4. With a scan tool, compare the battery temperature, ECT, and IAT sensor values.
Is the Engine Coolant Temperature Sensor value within 10° C (18° F) of the other two sensor values?
Yes
- Refer to the CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Checking for an Intermittent DTC.
No
- Go To 3
3. ENGINE COOLANT TEMPERATURE SENSOR VOLTAGE
1. Turn the ignition off.
2. Disconnect the Engine Coolant Temperature Sensor harness connector.
3. Turn the ignition on.
4. With a scan tool, read the Engine Coolant Temperature Sensor voltage.
NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the connector disconnected.
Does the scan tool display the voltage as described above?
Yes
- Go To 4
No
- Go To 5
4. ENGINE COOLANT TEMPERATURE SENSOR
1. Turn the ignition off.
2. Connect a jumper wire between the (K2) ECT Signal circuit and the (K900) Sensor Ground circuit in the Engine Coolant Temperature Sensor harness connector.
3. Turn the ignition on.
4. With a scan tool, read the Engine Coolant Temperature Sensor voltage.
NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus.1 volt) with the jumper wire in place.
Does the scan tool display the voltage as described above?
Yes
- Replace the Engine Coolant Temperature Sensor.
- Perform the PCM Verification Test. PCM Verification Test.
No
- Go To 5
5. (K2) ECT SIGNAL CIRCUIT HIGH RESISTANCE
1. Turn the ignition off.
2. Connect the Engine Coolant Temperature Sensor harness connector.
3. Using a voltmeter, perform a voltage drop test by backprobing the (K2) ECT Signal circuit at the Engine Coolant Temperature Sensor and Powertrain Control Module (PCM) harness connectors. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose fitting clothing. Failure to follow these instructions can result in personal or fatal injury.
4. Start the engine.
Is the voltage below 0.5 volts?
Yes
- Go To 6
No
- Repair the (K2) ECT Signal circuit for high resistance.
- Perform the PCM Verification Test. PCM Verification Test.
6. (K900) SENSOR GROUND CIRCUIT HIGH RESISTANCE
1. Turn the ignition off.
2. Using a voltmeter, perform a voltage drop test by backprobing the (K900) Sensor Ground circuit at the Engine Coolant Temperature Sensor and Powertrain Control Module (PCM) harness connectors. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose fitting clothing. Failure to follow these instructions can result in personal or fatal injury.
3. Start the engine.
Is the voltage below 0.5 volts?
Yes
- Go To 7
No
- Repair the (K900) Sensor Ground circuit for high resistance.
- Perform the PCM Verification Test. PCM Verification Test.
7. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Engine Coolant Temperature Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for a DTC to set during the wiggle test.
6. Search for any Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM Verification Test. PCM Verification Test.
No
- Replace the Powertrain Control Module (PCM).
- Perform the PCM Verification Test. PCM Verification Test.