2010 Cadillac Truck SRX FWD V6-3.0L Page 1141
2. Ignition Off all vehicle systems Off, this may take up to 2 minutes.Test for less than 5 ohm between the low reference circuit terminal A and
ground.
瀚慖f greater than the specified range, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit tests
normal, replace the K20 ECM.
3. Ignition ON, verify that the scan tool ECT sensor parameter is at -40掳C (-40掳F).
瀚慖f greater than the specified value, test the signal circuit terminal B 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.
4. Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the ECT
sensor parameter is greater than 142掳C (288掳F).
瀚慖f less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace
the K20 ECM.
5. If all circuits test normal, test or replace the B34 ECT sensor.
Component Testing
1. Ignition OFF, disconnect the harness connector at the B34 engine coolant temperature (ECT) sensor.
Note: 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 - Engine Coolant Temperature Sensor (See: Powertrain Management/Computers and Control
Systems/Specifications/Temperature Versus Resistance - Engine Coolant Temperature Sensor) table and verify that the resistance is within 5
% of the specification.
瀚慖f not within the specified range, replace the B34 ECT sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Engine Coolant Temperature Sensor Replacement (LF1) (See: Engine, Cooling and Exhaust/Cooling System/Engine - Coolant Temperature
Sensor/Switch/Coolant Temperature Sensor/Switch (For Computer)/Service and Repair)Engine Coolant Temperature Sensor Replacement
(LAU) (See: Engine, Cooling and Exhaust/Cooling System/Engine - Coolant Temperature Sensor/Switch/Coolant Temperature
Sensor/Switch (For Computer)/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
P0118
DTC P0117 or P0118 (LF1)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/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
