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Diagnostic Test

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR AN ACTIVE DTC 
    1. Turn the ignition on.
    2. With the scan tool, read DTCs.

      Is the DTC active or pending?

      Yes 

      • Go To  2

      No 

  2. CHECK THE (T110) VACUUM PUMP RELAY CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect the PCM C1 harness connector.
    3. Disconnect the PDC 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) to the engine harness side of the PCM C1 harness connector. Do not connect the GPEC Diagnostic Adaptor to the PCM.
    5. Check for continuity between the (T110) Vacuum Pump Relay Control circuit and all other circuits at the GPEC Adaptor.

      Is there continuity between the (T110) Vacuum Pump Relay Control circuit and any other circuit?

      Yes 

      • Repair the (T110) Vacuum Pump Relay Control circuit for a short to another circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L . .

      No 

      • Go To  3
  3. CHECK THE (T110) VACUUM PUMP RELAY CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (T110) Vacuum Pump Relay Control circuit from the PDC C2 harness connector to the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  4

      No 

      • Repair the (T110) Vacuum Pump Relay Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L . .
  4. CHECK THE (T110) VACUUM PUMP RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. Measure the continuity between ground and the (T110) Vacuum Pump Relay Control circuit at the GPEC Adaptor.

      Is there continuity between ground and the (T110) Vacuum Pump Relay Control circuit?

      Yes 

      No 

      • Go To  5
  5. CHECK THE PDC FOR DAMAGE 
    1. Reconnect the PDC C2 harness connector.
    2. Turn the ignition on, engine not running.
    3. Measure the voltage on the (T110) Vacuum Pump Relay Control circuit at the GPEC Adaptor.
      NOTE:

      Battery voltage should be present on the (T110) Vacuum Pump Relay Control circuit when the PCM is not commanding the relay on.

      Is Battery voltage present?

      Yes 

      • Go To  6

      No 

      • Check the fuses in the PDC. If a fuse is blown, replace it and retest the system. If all of the fuses are good, replace the Power Distribution Center (PDC) in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 3.2L . .
  6. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect all PCM harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. 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.

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

      Did the DTC return?

      Yes 

      No 

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