For a complete wiring diagram Refer to Section 8WWhen Monitored:With the ignition on.Set Condition:The Engine Control Module (ECM) detects an implausible voltage on the (K2) Engine Coolant Temperature Sensor Signal circuit.Possible CausesINTERMITTENT DTC(K2) ENGINE COOLANT TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE(K914) ENGINE COOLANT TEMPERATURE SENSOR GROUND CIRCUIT SHORTED TO VOLTAGE(K2) ENGINE COOLANT TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND(K2) ENGINE COOLANT TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO (K914) ENGINE COOLANT TEMPERATURE SENSOR GROUND CIRCUIT(K2) ENGINE COOLANT TEMPERATURE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE(K914) ENGINE COOLANT TEMPERATURE SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCEENGINE COOLANT TEMPERATURE SENSORENGINE CONTROL MODULE (ECM)Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)1. DTC IS ACTIVEIgnition on, engine not running.With the scan tool, Clear DTCs in the Engine Control Module (ECM).Monitor the scan tool for at least two minutes.Cycle the ignition key off and on several times, leaving the ignition on for at least 10 seconds at a time.Start the engine.Allow the engine to reach normal operating temperature.With the scan tool, select View DTCs.Is the status Active for this DTC?YesGo To 2 NoRefer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)2. (K2) ENGINE COOLANT TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE

Turn the ignition off.Disconnect the Engine Coolant Temperature Sensor harness connector.Disconnect the Engine Control Module (ECM) harness connector.Remove the ASD Relay from the TIPM.Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay Connector.Turn the ignition on.Measure the voltage of the (K2) Engine Coolant Temperature Sensor Signal circuit in the Engine Coolant Temperature Sensor harness connector.Is there any voltage present?YesRepair the (K2) Engine Coolant Temperature Sensor Signal circuit for a short to voltage.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 33. (K914) ENGINE COOLANT TEMPERATURE SENSOR GROUND CIRCUIT SHORTED TO VOLTAGE

The jumper wire should still be in place.Measure the voltage of the (K914) Engine Coolant Temperature Sensor Ground circuit in the Engine Coolant Temperature Sensor harness connector.Is there any voltage present?YesRepair the (K914) Engine Coolant Temperature Sensor Ground circuit for a short to voltage.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 44. (K2) ENGINE COOLANT TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND

Turn the ignition off.Remove the jumper wire and install the ASD Relay..Measure the resistance between ground and the (K2) Engine Coolant Temperature Sensor Signal circuit in the Engine Coolant Temperature Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 5NoRepair the (K2) Engine Coolant Temperature Sensor Signal circuit for a short to ground.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)5. (K2) ENGINE COOLANT TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO (K914) ENGINE COOLANT TEMPERATURE SENSOR GROUND CIRCUIT

Measure the resistance between the (K2) Engine Coolant Temperature Sensor Signal circuit and the (K914) Engine Coolant Temperature Sensor Ground circuit in the Engine Coolant Temperature Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 6NoRepair the (K2) Engine Coolant Temperature Sensor Signal circuit for a short to the (K914) Engine Coolant Temperature Sensor Ground circuit.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)6. (K2) ENGINE COOLANT TEMPERATURE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K2) Engine Coolant Temperature Sensor Signal circuit between the Engine Coolant Temperature Sensor harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms?YesGo to 7NoRepair the (K2) Engine Coolant Temperature Sensor Signal circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)7. (K914) ENGINE COOLANT TEMPERATURE SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K914) Engine Coolant Temperature Sensor Ground circuit between the Engine Coolant Temperature Sensor harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms?YesGo to 8NoRepair the (K914) Engine Coolant Temperature Sensor Ground circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)8. ENGINE COOLANT TEMPERATURE SENSOR

Connect the Engine Control Module (ECM) harness connector.Connect a jumper wire between the (K914) Engine Coolant Temperature Sensor Ground circuit and the (K2) Engine Coolant Temperature Sensor Signal circuit in the Engine Coolant Temperature Sensor harness connector.Turn the ignition on.With the scan tool, Clear DTCs.With the scan tool, select View DTCs.The scan tool should display an Engine Coolant Temperature Sensor low voltage or short to ground DTC with the jumper wire in place.Turn the ignition off.Remove the jumper wire.Turn the ignition on.With the scan tool, Clear DTCs.With the scan tool, select View DTCs.The scan tool should display an Engine Coolant Temperature Sensor high voltage or open circuit DTC with the Engine Coolant Temperature Sensor connector disconnected.Does the scan tool display the DTC(s) as described above?YesReplace the Engine Coolant Temperature Sensor.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 99. ENGINE CONTROL MODULE (ECM)Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Engine Coolant Temperature Sensor and the Engine Control Module (ECM).Look for any chafed, pierced, pinched, or partially broken wires.Look for broken, bent, pushed out or corroded terminals.Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.Look for the data to change or for the DTC to reset during the wiggle test.Refer to any Technical Service Bulletins that may apply.Were any problems found?YesRepair as necessary.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace the Engine Control Module (ECM) in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)