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Pinpoint Test N: Linear O2 (Oxygen) Sensor Control Chip

WARNING: This page is about a different car, the 2023 Ford Transit-350 HD, 2023 Ford Transit-350, 2023 Ford Transit-250, and 2023 Ford Transit-150. However, it is still accessible from the selected car via links, so may be relevant.
  1. Refer to ELECTRONIC ENGINE CONTROLS - 3.5L GTDI for schematic and connector information.

    Normal Operation and Fault Conditions 

    Refer to the DTC Fault Trigger Conditions. REFER to: Fuel Charging and Controls - System Operation and Component Description . for additional information.

    DTC Fault Trigger Conditions 

    DTC Description Fault Trigger Condition
    PCM P1646:00 Linear O2 Sensor Control Chip (Bank 1): No Sub Type Information The PCM sets this DTC when an internal circuit or communication concern is detected. The PCM monitors the application specific integrated circuit that controls and monitors the universal HO2S (bank 1).
    PCM P1647:00 Linear O2 Sensor Control Chip (Bank 2): No Sub Type Information The PCM sets this DTC when an internal circuit or communication concern is detected. The PCM monitors the application specific integrated circuit that controls and monitors the universal HO2S (bank 2).

    Possible Sources 

    • Universal HO2S circuit concern
    • Damaged or corroded electrical connector
    • PCM software
    • PCM

    Visual Inspection and Pre-checks 

    • Inspect electrical connectors for signs of damage, water ingress or corrosion.

  2. N1 CHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) S

    NOTE: Diagnose all other powertrain related DTC s first.

    • Ignition ON.

    • Using a diagnostic scan tool, retrieve all DTC s from the PCM.

    Are DTC s P1646 or P1647 present? 

    Yes  GO to  N2
    No  The system is operating correctly at this time.

  3. N2 VISUALLY INSPECT THE UNIVERSAL HO2S (HEATED OXYGEN SENSOR) WIRING HARNESS

    • Ignition OFF.

    • Disconnect Universal HO2S (bank 1) C1510 or universal HO2S (bank 2) C1631.

    • Visually inspect the universal HO2S wiring harness and electrical connectors for:

      • Crossed sensor wiring
      • Pinched, shorted or corroded wiring
      • Oil or water contamination in wiring harness or electrical connector
      • Damaged or bent pins
      • Pushed out pins
      • Spread terminals

    Is a concern present? 

    Yes  REPAIR as necessary.CLEAR the PCM DTCs. REPEAT the self-test.
    No  GO to  N3

  4. N3 CHECK FOR MISFIRE CONCERNS AND AFTERMARKET EQUIPMENT

    • Check for the following:

      • Engine misfire concern
      • Non-factory or aftermarket equipment fitted to vehicle that may increase exhaust temperature

    Is a concern present? 

    Yes  REPAIR as necessary.CLEAR the PCM DTCs. REPEAT the self-test.
    No  GO to  N4

  5. N4 CHECK FOR CORRECT PCM (POWERTRAIN CONTROL MODULE) OPERATION

    • Ignition OFF.

    • Inspect PCM C1551T electrical connector.

    • Using a good light source, inspect the PCM electrical connector for the following:

      • Corrosion - install new connector or terminal and clean the module pins
      • Damaged or bent pins - install new terminals or pins
      • Pushed-out pins - install new pins as necessary
      • Spread terminals - install new terminals as necessary

    • Connect PCM C1551T electrical connector. Make sure it seats and latches correctly.

    • Connect universal HO2S (bank 1) C1510 or universal HO2S (bank 2) C1631 electrical connector. Make sure it seats and latches correctly.

    • Ignition ON.

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

    Is the concern still present? 

    Yes  GO to  N5
    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.

  6. N5 PROGRAM THE PCM (POWERTRAIN CONTROL MODULE) WITH THE LATEST CALIBRATION

    • Ignition ON.

    • Using a diagnostic scan tool, reprogram the PCM with the latest calibration.

    • Using a diagnostic scan tool, carry out the PCM self-test.

    Did the DTC return? 

    Yes  CHECK OASIS for any applicable service articles: TSB, GSB (general service bulletin), SSM (special service message) or FSA (Field Service Action). 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 PCM. REFER to: Powertrain Control Module (PCM)
    CLEAR the PCM DTCs. REPEAT the self-test.
    No  The fault is not present at this time. It may have been caused by a module programming error.
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