2010 Cadillac CTS Sedan AWD V6-3.6L Page 1034
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning)for scan tool information
Circuit/System Verification
1. Observe the scan tool engine coolant temperature (ECT) sensor parameter, while moving the ECT sensor connector and the K20 ECM
connector. The ECT sensor parameter should not fluctuate while moving the related harnesses and connectors.
瀚慠epair the suspected harness or connection if the ECT parameter fluctuates greater than 3掳C (5掳F) while moving the related harnesses and
connectors.
2. Inspect the engine coolant level. Verify that the cooling system is operating correctly.
瀚慖f you suspect a condition with engine cooling system, refer to Loss of Coolant (See: Engine, Cooling and Exhaust/Cooling
System/Testing and Inspection/Symptom Related Diagnostic Procedures/Loss of Coolant).
3. 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
1. Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
2. Ignition OFF, remove the fuse that supplies B+ to circuit terminal 56 X2 of the K20 ECM.
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.
3. Test for less than 5 ohm between the low reference circuit terminal 2 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.
4. Install the fuse that supplies B+ to circuit terminal 56 X2 of the K20 ECM.
5. Ignition ON, verify that the scan tool ECT sensor parameter is at -40掳C (-40掳F).
瀚慖f warmer than the specified value, 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.
6. Ignition ON, install a 3A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. 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.
7. 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)
table and verify that the resistance is within 5 percent 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
