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Home >> Ford >> 2021 >> Explorer Limited Hybrid, RWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Electric Powertrain Control - 3.3L DURATEC-V6 - Hybrid (BP) (2 Of 2) >> Diagnosis And Testing >> Electric Powertrain Control >> Pinpoint Tests >> Pinpoint Test Z : P0A71, P0A74, P0A77

Pinpoint Test Z : P0A71, P0A74, P0A77

  1. 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 P0A71:00 Generator Phase U Current High: No Sub Type Information This DTC sets when the U phase current is outside of the normal range.
    SOBDMC P0A74:00 Generator Phase V Current High: No Sub Type Information This DTC sets when the V phase current is outside of the normal range.
    SOBDMC P0A77:00 Generator Phase W Current High: No Sub Type Information This DTC sets when the W phase current is outside of the normal range.

    Possible Sources 

    • Wiring, terminals or connectors
    • Low Voltage wiring
    • Other Inverter System Controller (ISC) DTCs
    • Inverter System Controller (ISC) TRID block programming
    • Inverter System Controller (ISC)

  2. Z1 CHECK FOR OTHER DIAGNOSTIC TROUBLE CODES (DTCS)

    • Ignition ON.

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

    Are DTCs P0634, P0A4D, P0A47, P0A6F, P0A7A:96, P0C5A, P0C5C, P0C5D, P0C5F, P0C61, P0C62, P0C64, P0C66, P0C67, P0C6A, P0C6B, P0C6C, P0A72, or P0A75 present? 

    Yes  DIAGNOSE these Inverter System Controller (ISC) DTCs. REFER to the Diagnostic Trouble Code (DTC) Chart  .
    No  GO to  Z2

  3. Z2 CHECK THE INVERTER SYSTEM CONTROLLER (ISC) CALIBRATION LEVEL

    • Verify the Inverter System Controller (ISC) is at the latest calibration level.

    Is the Inverter System Controller (ISC) at the latest calibration level? 

    Yes  GO to  Z2
    No  UPDATE the Inverter System Controller (ISC) to the latest calibration level.

  4. Z3 READ THE INVERTER SYSTEM CONTROLLER (ISC) DIAGNOSTIC TROUBLE CODES (DTCS)

    • Using a diagnostic scan tool, retrieve the Inverter System Controller (ISC) DTCs.

    Are P0A71, P0A74 or P0A77 the only DTCs present? 

    Yes  GO to  Z4
    No  DIAGNOSE all other Inverter System Controller (ISC) DTCs. REFER to the Diagnostic Trouble Code (DTC) Chart  .

  5. Z4 VISUAL INSPECTION OF THE HIGH VOLTAGE SYSTEM

    • Ignition OFF.

    • Remove the high voltage traction battery service disconnect plug.

    • Visually inspect all the high voltage cables.

    • Make sure all the high voltage connectors are correctly and securely connected.

    • Examine all the high voltage cables and connectors for damaged, burned or overheated insulation and loose or broken connections.

    • Make sure the high voltage DC connector cover is correctly installed and it was not removed from the vehicle.

    Is a concern present? 

    Yes  REPAIR as necessary. CLEAR the DTCs and REPEAT the self-test.
    No  GO to  Z5

  6. Z5 CHECK THE ELECTRIC MOTOR CIRCUITS FOR AN OPEN

    • Disconnect Electric Motor C1201.

    • Disconnect Inverter System Controller (ISC) C1458B.

    Are the resistances less than 5 ohms? 

    Yes  GO to  Z6
    No  REPAIR the open circuit. CLEAR the DTCs and REPEAT the self-test.

  7. Z6 CHECK THE ELECTRIC MOTOR CIRCUITS FOR A SHORT TO GROUND

    • Measure and record:
      Positive Lead Measurement / Action Negative Lead
      C1201-1
      GFD513961Courtesy of FORD MOTOR COMPANY
      		 Ground
      C1201-2
      GFD513961Courtesy of FORD MOTOR COMPANY
      		 Ground
      C1201-3
      GFD513961Courtesy of FORD MOTOR COMPANY
      		 Ground

    Are the resistances greater than 10K ohms? 

    Yes  GO to  Z7
    No  REPAIR the short circuit. CLEAR the DTCs and REPEAT the self-test.

  8. Z7 CHECK THE ELECTRIC MOTOR CIRCUITS FOR SHORTED TOGETHER

    • Measure and record:
      Positive Lead Measurement / Action Negative Lead
      C1201-1
      GFD513961Courtesy of FORD MOTOR COMPANY
      		 C1201-2
      C1201-1
      GFD513961Courtesy of FORD MOTOR COMPANY
      		 C1201-3
      C1201-2
      GFD513961Courtesy of FORD MOTOR COMPANY
      		 C1201-3

    Are the resistances greater than 10K ohms? 

    Yes  GO to  Z8
    No  REPAIR the short circuit. CLEAR the DTCs and REPEAT the self-test.

  9. Z8 CHECK FOR CORRECT INVERTER SYSTEM CONTROLLER (ISC) OPERATION

    • Ignition OFF.

    • Disconnect and inspect all Inverter System Controller (ISC) connectors.

    • 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

    • Reconnect the Inverter System Controller (ISC) connectors. Make sure they seat and latch correctly.

    • Connect Electric Motor C1201.

    • Ignition ON.

    • Clear the Inverter System Controller (ISC) DTCs.

    • Ignition OFF.

    • Start the engine.

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

    Are any DTCs present? 

    Yes  DIAGNOSE all other Inverter System Controller (ISC) DTCs. REFER to the Diagnostic Trouble Code (DTC) Chart  .
    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.
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