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Home >> Jeep >> 2021 >> Cherokee Trailhawk >> Repair and Diagnosis >> Engine Performance >> System >> 3.2L - DTCS P0073 To P0298 >> DTC Troubleshooting >> P0116-Engine Coolant Temperature Sensor Performance >> Diagnostic Test
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Diagnostic Test

  1. CHECK FOR AN ACTIVE CONDITION 
    1. Turn the ignition off.
    2. Allow the vehicle to sit with the ignition off in an environment where the temperature is consistent and above -64°C (-83°F) until the engine coolant temperature is equal, or close to the environmental ambient temperature.
    3. Turn the ignition on.
    4. With the scan tool, compare the AAT, ECT and IAT sensor values.

      Is the Engine Coolant Temperature Sensor value within 15°C (27°F) of the other two sensor values?

      Yes 

      No 

      • Go To  2
  2. CHECK THE (K2) ECT SIGNAL CIRCUIT FOR HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the ECT Sensor harness connector.
    3. Disconnect the PCM C2 harness connector.
      CAUTION:

      Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.

    4. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
    5. Measure the resistance of the (K2) ECT Signal circuit between the ECT Sensor harness connector and the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  3

      No 

      • Repair the (K2) ECT Signal circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  3. CHECK THE (K915) SENSOR GROUND CIRCUIT FOR HIGH RESISTANCE 
    1. Measure the resistance of the (K915) Sensor Ground circuit between the ECT Sensor harness connector and the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  4

      No 

      • Repair the (K915) Sensor ground circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  4. CHECK THE ABILITY OF THE PCM TO READ THE ECT SENSOR SIGNAL 
    1. Turn the ignition off.
    2. Reconnect the PCM C2 harness connector.
    3. Turn the ignition on.
    4. With the scan tool, read the ECT Sensor voltage.
      NOTE:

      The sensor voltage should be approximately 5.0 volts (plus or minus 0.1 volts) with the connector disconnected.

    5. Connect a jumper between the (K2) ECT Signal circuit and the (K915) Sensor Ground circuit at the ECT Sensor harness connector.
      NOTE:

      The sensor voltage should be approximately 0.0 volts (plus or minus 0.1 volts) with the jumper in place.

      Does the scan tool display the voltage as described above?

      Yes 

      • Replace the Engine Coolant Temperature Sensor in accordance with the Service Information. Refer to 3.2L .
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK RELATED PCM AND COMPONENT CONNECTIONS 
    1. Perform any Service Bulletins that apply.
    2. Disconnect all PCM harness connectors.
    3. Disconnect all related in-line harness connections (if equipped).
    4. Disconnect the related component harness connectors.
    5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    9. With the scan tool, erase DTCs.
    10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    11. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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