P0116
P0116-ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT PERFORMANCEP0116-Engine Coolant Temperature Sensor Circuit Performance:
Theory of Operation
Engine Coolant Temperature Sensor performance looks at the outputs of three temperature sensors and compare them under cold start conditions. Following a start to run delay time, the outputs of the ambient, engine coolant, and intake air temperature sensors will be compared. If the intake air and ambient air temperature sensors agree and the engine coolant temperature does not agree, the engine coolant temperature sensor is declared as irrational.
WHEN MONITORED
Engine off time is greater than 480 minutes. Ambient temperature is greater than 4 deg C (38 deg F).
SET CONDITION
After a calibrated amount of cool down time the PCM compares the ECT Sensor, IAT Sensor, and the Ambient Air Temp Sensor values. If the ECT Sensor value is not within 10 deg C of the other two temperature sensors. Two Trip Fault. Three good trips to turn off the MIL. (5.7L ETC lamp will illuminate with the MIL.)
POSSIBLE CAUSES
- (K2) ECT signal circuit shorted to battery voltage
- (K2) ECT signal circuit open
- (K900) Sensor ground circuit open
- (K2) ECT signal circuit shorted to ground
- (K2) ECT signal circuit shorted to the (K900) sensor ground
- ECT sensor
- PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.
Q: Is the DTC active at this time?
YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Component Tests and General Diagnostics
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
2. (K2) ECT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the C2 PCM harness connector.
Disconnect the ECT Sensor harness connector.
NOTE: Visually inspect both the component and the PCM connectors. Look for damaged, partially broken wires, and backed out or corroded terminals.
Ignition on, engine not running.
Measure the voltage on the (K2) ECT Signal circuit in the ECT Sensor harness connector.
Q: Is the voltage above 0 volts?
YES: Repair the short to battery voltage in the (K2) ECT Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 3
3. ECT SENSOR VOLTAGE ABOVE 4.6 VOLTS
Turn the ignition off.
Connect the C2 PCM harness connector.
Ignition on, engine not running.
With a scan tool, read the ECT voltage.
Q: Is the voltage above 4.6 volts?
YES: Go To 4
NO: Go To 7
4. ECT SENSOR
Connect a jumper wire between the (K2) ECT Signal circuit and the (K900) Sensor ground circuit in the ECT Sensor harness connector.
With a scan tool, read the ECT voltage.
Q: Is the voltage below 1.0 volt with the jumper wire installed?
YES: Replace the ECT Sensor. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 5
NOTE: Remove the jumper wire before continuing.
5. (K2) ECT SIGNAL CIRCUIT OPEN
Turn the ignition off.
Disconnect the C2 PCM harness connector.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (K2) ECT Signal circuit from the ECT Sensor harness connector to the appropriate terminal of special tool #8815.
Q: Is the resistance below 5.0 ohms?
YES: Go To 6
NO: Repair the open in the (K2) ECT Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
6. (K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the ECT Sensor harness connector to the appropriate terminal of special tool #8815.
Q: Is the resistance below 5.0 ohms?
YES: Go To 9
NO: Repair the open in the (K900) Sensor ground circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
7. (K2) ECT SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C2 PCM harness connector.
Measure the resistance between ground and the (K2) ECT Signal circuit in the ECT Sensor harness connector.
Q: Is the resistance below 100 ohms?
YES: Repair the short to ground in the (K2) ECT Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 8
8. (K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance between the (K2) ECT Signal circuit and the (K900) Sensor ground circuit in the ECT Sensor harness connector.
Q: Is the resistance below 5.0 ohms?
YES: Repair the short between the (K900) Sensor ground circuit and the (K2) ECT Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 9
9. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Q: Were there any problems found?
YES: Repair as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Replace and program the Powertrain Control Module. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test