Service Information

Spark

DTC P0117 or P0118 - FX3

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 Descriptors

DTC P0117: Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage

DTC P0118: Engine Coolant Temperature (ECT) Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Signal	P0117	P0118	P0118*	P0116
Low Reference	-	P0118	P0118*	P0116
* ECM or 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 running in closed loop Parameter Normal Range: Varies with ambient temperature
Signal	215°C (419°F)	-40°C (-40°F)	-40°C (-40°F)
Low Reference	-	-40°C (-40°F)	-40°C (-40°F)
ECM or 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 5V to the ECT signal circuit and 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

•	DTC P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0335, P0336, P0351, P0352, P0353, P0354, P0480, P0481, P0502, P0562, P0563, P2110, or P2610 is not set.

•	The engine is running.

•	The intake air temperature is greater than -10°C (14°F).

•	The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P0117

The ECM detects that the ECT sensor signal voltage is less than 0.1V.

P0118

The ECM detects that the ECT sensor signal voltage is greater than 4.9V.

Action Taken When the DTC Sets

DTC P0117 and P0118 are Type E DTCs.

Conditions for Clearing the DTC

DTC P0117 and P0118 are Type E DTCs.

Diagnostic Aids

•

Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor. Engine coolant that is leaking through the sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a warmer ECT.

•	Test the ECT sensor at various temperature levels in order to evaluate the possibility of a biased sensor. A sensor that is biased warmer can result in a driveability condition. Refer to Temperature Versus Resistance .

•

If the condition is intermittent, allowing the vehicle to sit for greater than 8 hours with the ignition OFF, may help isolate the condition. Compare the scan tool ECT sensor and IAT sensor temperature values at Ignition ON. The ECT sensor and the IAT sensor values should display within 3°C (5°F) of each other.

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

Reference Information

Schematic Reference

Engine Controls Schematics : Siemens ECM - LPG with LCP → Siemens ECM - Gas without FX3 or LCP → Delphi ECM - FX3

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

Verify that DTC P0112, P0113, P0117, or P0118 is not set.

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

Ignition OFF, inspect the cooling system surge tank for the proper coolant level. Refer to Loss of Coolant and Cooling System Draining and Filling .
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, disconnect the harness connector at the B34 engine coolant temperature (ECT) sensor.
Ignition OFF for 1 minute, test for less than 5 Ω between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.

Ignition ON, verify the scan tool ECT sensor parameter is less than -39°C (-38.2°F).

⇒	If greater than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 ECM.

Note: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.

Install a 3A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool ECT sensor 1 parameter is greater than 214°C (417.2°F).

⇒	If less than specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

If all circuits test normal, test or replace the B34 ECT sensor.

Component Testing

Ignition OFF, disconnect the harness connector at the B34 ECT sensor.

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

Test the B34 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 B34 ECT sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Engine Coolant Temperature Sensor Replacement : Thermostat → Radiator

•	Control Module References for ECM replacement, setup, and programming