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Pinpoint Test BO : U351F

  1. NOTE: The Inverter System Controller (ISC) is referred to as the SOBDMC (Secondary On-Board Diagnostic Control Module C) in the scan tool.

    Normal Operation and Fault Conditions 

    REFER to: Electric Powertrain Control - System Operation and Component Description .

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    SOBDMC U351F:00 High Voltage System Interlock Circuit "E" Low: No Sub Type Information This DTC sets when difference is detected between the battery and the PTC heater.

    Possible Sources 

    • Wiring, terminals or connectors
    • PTC heater

  2. BO1 REVIEW AND RECORD THE INVERTER SYSTEM CONTROLLER (ISC) DIAGNOSTIC TROUBLE CODES (DTCS)

    • Ignition ON.

    • Using a diagnostic scan tool, run the Inverter System Controller (ISC) self-test.

    Is DTC U351F present? 

    Yes  GO to  BO2
    No  The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

  3. BO2 CHECK THE CABIN COOLANT HEATER FOR BEING FULLY SEATED

    • Ignition OFF.

    • Check that the Cabin Coolant Heater C1815B is connected and fully seated.

    Was the connector connected and fully seated? 

    Yes  GO to  BO3
    No  RECONNECT the connector and verify it is fully seated. Repower the high voltage system. REFER to: High Voltage System De-energizing .

  4. BO3 INSPECT THE CABIN COOLANT HEATER CONNECTOR

    • Ignition OFF.

    • Disconnect C1815B.

    • Repair:

      • Corrosion (install new connector or terminals - clean module pins)
      • Damaged or bent pins - install new terminals/pins
      • Pushed-out pins - install new pins as necessary

    Is a concern present? 

    Yes  INSTALL a new High Voltage Cable assembly. REFER to: High Voltage Battery Cables - Hybrid Electric Vehicle (HEV) . CLEAR the Inverter System Controller (ISC) DTCs. REPEAT the self-test.
    No  GO to  BO4

  5. BO4 CHECK FOR CORRECT CABIN COOLANT HEATER OPERATION

    • Ignition OFF.

    • Connect C1815B.

    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes  CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new PTC heater. REFER to the appropriate Service Information .
    No  The system is operating correctly at this time. The concern may have been caused by module connections. Address the root cause of any connector or pin issues.
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