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Pinpoint Test Bn : U351B

  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 U351B:00 High Voltage System Interlock Circuit "D" Low: No Sub Type Information This DTC sets when a difference is detected between the high voltage battery and the electric AC module.

    Possible Sources 

    • Wiring, terminals or connectors
    • ACCM

  2. BN1 REVIEW AND RECORD THE INTERLOCK DIAGNOSTIC TROUBLE CODES (DTCS)

    • Ignition ON.

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

    Is DTC U351B present? 

    Yes  GO to  BN2
    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. BN2 CHECK THE ACCM (AIR CONDITIONING CONTROL MODULE) ELECTRIC COMPRESSOR HIGH VOLTAGE CABLE FOR BEING FULLY SEATED

    • Ignition OFF.

    • Check that the ACCM C1803B is connected and fully seated.

    Was the connector connected and fully seated? 

    Yes  GO to  BN3
    No  RECONNECT the connector and verify it is fully seated. Repower the high voltage system. REFER to: High Voltage System De-energizing . Operate the system and determine if the concern is still present.

  4. BN3 INSPECT THE ACCM (AIR CONDITIONING CONTROL MODULE) CONNECTOR

    • Ignition OFF.

    • Disconnect ACCM C1803B.

    • 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) .
    No  GO to  BN4

  5. BN4 CHECK FOR CORRECT ACCM (AIR CONDITIONING CONTROL MODULE) ELECTRIC COMPRESSOR OPERATION

    • Ignition OFF.

    • Connect ACCM C1803B.

    • 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 ACCM and Electric Compressor Assembly. REFER to: Air Conditioning (A/C) Compressor - 2.5L Duratec - Hybrid (121kW/164PS) (BG) .
    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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