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Home >> Kia >> 2019 >> Optima S >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System Diagnosis - 2.4L (6 Of 6) (Except HEV) >> DTC U0109-00: Lost Communication With Fuel Pump Control Module >> Wiring Inspection >> CAN Communication Line Inspection >> Short in CAN Communication Line Inspection
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Short in CAN Communication Line Inspection

  1. Ignition "ON".
  2. Measure voltage between Pin No. 3 (C-CAN High) terminal of Data Link Connector (DLC) and chassis ground.
  3. Measure voltage between Pin No. 11 (C-CAN Low) terminal of Data Link Connector (DLC) and chassis ground.

    Specification:  CAN High Voltage - Approx. 2.6 V/CAN Low Voltage - Approx. 2.4 V

  4. Is the measured value within specification?

    YES 

    • Fault might be intermittent and caused either by poor contact in connectors or wiring harness, or it has been repaired and control module memory is not cleared yet. Thoroughly check terminal of battery, all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/or damage.
    • Repair or replace as necessary and then go to "VERIFICATION OF REPAIR" procedure.

    NO 

    • Go to next procedure.


  1. Ignition "OFF".
  2. Disconnect Battery (-) terminal.
  3. Refer to "Appropriate Service Information" and disconnect Cluster, ECM, TCM, HECU and other control unit connector that connected to C-CAN Communication circuit.
  4. Measure resistance between Pin No. 3 (C-CAN High) terminal and Pin No. 11 (C-CAN Low) terminal of Data Link Connector (DLC).

    Specification:  Infinite (∞) Ω

  5. Is the measured value within specification?

    YES 

    • Go to "COMPONENT INSPECTION" procedure.

    NO 

    • Repair short in C-CAN Communication circuit or replace as necessary and then go to "VERIFICATION OF VEHICLE REPAIR" procedure.
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