Vue 2006-2007

Testing

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Fig. Engine Coolant Temperature (ECT) sensor connector end view-2.2L & 2.4L engines



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Fig. Engine Coolant Temperature (ECT) sensor connector end view (sensor 1)-3.5L engine



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Fig. Engine Coolant Temperature (ECT) sensor connector end view (sensor 2)-3.5L engine


NOTE
If the PCM receives a high engine temperature signal from the Engine Coolant Temperature (ECT), it adjusts fueling rates to protect the engine from damage due to overheating.

  1. Turn OFF the ignition.
  2.  
  3. Inspect the cooling system surge tank for the proper coolant level.
  4.  
  5. If the ignition has been OFF for 8 hours or more, the ECT and the Intake Air Temperature (IAT) should be within 27°F (15°C) of each other and also the ambient temperature.
  6.  
  7. Turn ON the ignition, with the engine OFF, and use a scan tool to observe the IAT and the ECT sensor parameters.
  8.  
  9. Use the scan tool to verify the proper operation of the engine cooling system fans.
    NOTE
    A critical analysis of the operation of the thermostat is important to the proper diagnosis of the ECT.

  10.  
  11. Verify the proper heat range and the operation of the thermostat.
  12.  

Circuit/System Testing




NOTE
All electrical components and accessories must be turned OFF and allowed to power down.

  1. With the ignition OFF, disconnect the harness connector at the ECT sensor.
  2.  
  3. Test for less than 5 ohms of resistance between the low reference circuit terminal and ground.
    1. If greater than the specified range, test the low reference circuit for an open/high resistance.
    2.  
    3. If the circuit tests normal, replace the ECM.
    4.  

  4.  
  5. With the ignition ON, verify the scan tool ECT parameter is less than a negative 38°F (negative 39°C).
    1. If greater than the specified range, test the signal circuit terminal for a short to ground.
    2.  
    3. If the circuit tests normal, replace the ECM.
    4.  

  6.  
  7. Install a 3-amp fused jumper wire between the signal circuit terminal and the low reference circuit terminal. Verify the scan tool ECT parameter is greater than 300°F (149°C).
    1. If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance.
    2.  
    3. If the circuit tests normal, replace the ECM.
    4.  

  8.  
  9. If all circuits test normal, test or replace the ECT sensor.
  10.  

ECT Component Testing



Measure and record the resistance of the ECT sensor at various temperatures, then compare those measurements to the following temperature verses resistance table.

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Fig. Temperature verses resistance table for ECT sensor

 
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