Service Information

Captiva

DTC P0116

Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0116: Engine Coolant Temperature (ECT) Sensor Performance

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
ECT Sensor Signal	P0117	P0118	P0118	P0116*
Low Reference	-	P0118	P0118	P0116*
* Internal ECM or ECT sensor 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:* -39 to +128°C (-38 to +262°F) Varies with coolant temperature.
ECT Sensor Signal	143°C (289°F)	-40°C (-40°F)	-40°C (-40°F)¹
Low Reference	-	-40°C (-40°F)	-40°C (-40°F)¹
¹ Internal ECM or ECT sensor damage may occur if the circuit is shorted to B+

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 an ground to the low reference circuit. The ECM monitors the mutual performance of the ECT and the intake air temperature (IAT) signals. The ECM monitors the warm up and cool down behavior of the sensors, after a vehicle driven at operating temperature is shut down. If the ECM detects that the ECT is not with in a predetermined range of IAT after a long soak, or the ECT and IAT are not within a range of each other, as compared to a previous cold start, this DTC sets.

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

•	The ignition is ON

•	No block heater detected

•	The DTC runs once an ignition cycle when the above conditions are met.

Conditions for Setting the DTC

•	The ECM determines the difference between the measured ECT and the calculated ECT is not within 15°C (59°F).

•	Either condition exists for greater than 2 seconds.

Action Taken When the DTC Sets

DTC P0116 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P0116 is a Type B DTC.

Diagnostic Aids

•	Test the ECT and the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a DTC or a driveability condition. Refer to Temperature Versus Resistance .

•	If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).

•	After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilise after the thermostat opens.

•	High resistance in the circuits of either the ECT or IAT sensor could set a DTC.

•	A short to ground or voltage through a conductive material or fluid could set this DTC. Inspect the ECT sensor for evidence of coolant leaking into the connector body.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the DTC information with a scan tool. DTCs P0116, P0117 and P0118 should not set.
Inspect the engine coolant level. Verify the cooling system is operating correctly.

⇒	If you suspect a condition with engine cooling system, refer to Symptoms - Engine Cooling .

Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

Ignition OFF, and the MAIN fuse removed, disconnect the harness connector at the ECT sensor.

Caution: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.

Note: The control module or the sensor may be damaged if the circuit is shorted to battery positive voltage.

Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

Install the MAIN fuse. Ignition ON, verify the scan tool ECT sensor parameter is at -40°C (-40°F).

⇒	If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

Ignition ON, install a 3A 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 128°C (262°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 ECM.

If all circuits test normal, test or replace the ECT sensor.

Component Testing

Ignition OFF, disconnect the harness connector at the ECT sensor.

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

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 not within the specified range, replace the ECT sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Engine Coolant Temperature Sensor Replacement : LE5 , LE9 or LAF

•	Control Module References for engine control module replacement, setup, and programming