CTS 2006-2007, CTS-V 2005-2007, DTS 2006-2007

Testing

Print

  1. If the ignition has been OFF for 8 hours or more, the ECT and the IAT, should be within 11°F (6°C) of each other and also the ambient temperature. Turn ON the ignition, with the engine OFF, and use a scan tool to observe the IAT and the ECT sensor parameters. Compare those sensor parameters to each other and also to the ambient temperature. A slight to moderate resistance in the IAT signal or low reference circuit, can widen the spread between the two sensors and cause this DTC to set.
  2.  
  3. An IAT sensor that is skewed lower at various ambient temperatures, due to more resistance than is normal, can widen the spread between the two sensors and cause this DTC to set. Measure and record the resistance of the IAT sensor at various ambient temperatures, and then compare those measurements to the Temperature vs Resistance Table. Refer to Temperature Versus Resistance.
  4.  
  5. Turn OFF the ignition.
  6.  
  7. Inspect the ECT sensor terminals for corrosion, and for engine coolant leaking through the sensor.
  8.  

2.8L & 3.6L Engines



  1. Ignition OFF, disconnect the ECT sensor.
  2.  
  3. Ignition ON, verify that the ECT sensor parameter is at -40°F (-40°C).
  4.  
  5. If greater than -40°C (-40°F), test the signal circuit of the ECT sensor for a short to ground. If the circuit/connections test normal, replace the ECM.
  6.  
  7. Ignition OFF, remove the ECM/TCM fuse from the underhood fuse block.
    WARNING
    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.

  8.  
  9. Test for less than 5 ohms between the low reference circuit and the ECM housing.
  10.  
  11. If greater than 5 ohms, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit/connections test normal, replace the ECM.
  12.  
  13. Ignition OFF, install the ECM/TCM fuse to the underhood fuse block.
  14.  
  15. Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor and verify the ECT sensor parameter is greater than 288°F (142°C).
  16.  
  17. If less than 289°F (143°C), test the signal circuit of the ECT sensor for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.
  18.  
  19. If all circuits/connections test normal, replace the ECT sensor.

    Click image to see an enlarged view

    Fig. Engine Coolant Temperature (ECT) sensor electrical connector 2.8L & 3.6L engines

  20.  

4.6L, 5.7L & 6.0L Engines



  1. Ignition OFF, disconnect the ECT harness connector at the ECT sensor.
  2.  
  3. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal B and ground.
  4.  
  5. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  6.  
  7. Ignition ON, verify the scan tool ECT Sensor parameter is less than -38°F (-39°C).
  8.  
  9. If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
  10.  
  11. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool ECT Sensor parameter is greater than 300°F (149°C).
  12.  
  13. 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.
  14.  
  15. If all circuits test normal, test or replace the ECT sensor.

    Click image to see an enlarged view

    Fig. Engine Coolant Temperature (ECT) sensor electrical connector 4.6L, 5.7L & 6.0L Engines

  16.  

 
label.common.footer.alt.autozoneLogo