Diagnostic Instructions

DTC Descriptors

DTC P1114: Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage

DTC P1115: Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
ECT Sensor Signal	P0117, P1114	P0118, P1115	P0118, P1115¹	P0115
Low Reference	--	P0118, P1115	--	P0115
¹ Internal ECM damage may occur if the circuit is shorted to B+.

Typical Scan Tool Data

ECT Sensor

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: Varies with ambient temperature
ECT Sensor Signal	129°C (264°F), 0.0 Volts	-40°C (-40°F), 5.0 Volts	-40°C (-40°F), 5.0 Volts¹
Low Reference	--	-40°C (-40°F), 5.0 Volts	--
¹ Internal ECM damage may occur if the circuit is shorted to B+.

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 signal circuit and supplies a ground to the low reference circuit.

The following table illustrates the difference between temperature, resistance, and voltage:

ECT	ECT Resistance	ECT Signal Voltage
Cold	High	High
Warm	Low	Low

Conditions for Running the DTC

Conditions for Setting the DTC

P1114

The ECM detects that the ECT sensor is more than 149°C (300°F ) intermittently.

P1115

The ECM detects that the ECT sensor is less than -38°C (-34°F) intermittently.

Action Taken When the DTC Sets

DTCs P1114 and P1115 are Type C DTCs.

Conditions for Clearing the MIL/DTC

DTCs P1114 and P1115 are Type C DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Circuit/System Verification

1. Verify that DTCs P0117 or P0118 are not set.

⇒	If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

2. 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. DTC P1114 or P1115 should not set.
3. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

Circuit/System Testing

1. Start the engine. Observe the engine coolant temperature (ECT) sensor parameter while moving the harness connector of the sensor. The ECT sensor parameter should not change abruptly.

⇒	If the ECT sensor parameter changes abruptly, repair the harness connector of the ECT sensor.

2. Engine running, observe the ECT sensor parameter while moving the harness connector of the ECM. The ECT sensor parameter should not change abruptly.

⇒	If the ECT sensor parameter changes abruptly, repair the harness connector of the ECM.

3. Engine running, observe the ECT sensor parameter while moving the wiring harness between the sensor and ECM. The ECT sensor parameter should not change abruptly.

⇒	If the ECT sensor parameter changes abruptly, repair the wiring harness.

Component Testing

1. Ignition OFF, disconnect the harness connector of the ECT sensor.

Important: A thermometer can be used to test the sensor off the vehicle.

2. Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance table and verify that the resistance is within 5 percent of the specification.

⇒	If the resistance vs. temperature is not within 5 percent, replace the ECT sensor.

Repair Instructions