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Pinpoint Tests OB: The Selectable Drive Mode Feature Is Inoperative

Refer to the Parking Aid wiring diagrams, for schematic and connector information.

CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
  1. OB1: CHECK FOR OTHER ABS MODULE DTCS 
    • Ignition ON, engine OFF.

      Carry out the ABS self-test.

    • Are any battery voltage or lost communication DTCs present in the ABS module? 
      Yes No
      DIANOSE all ABS module battery voltage and lost communication DTCs before diagnosing the selectable drive mode switch. GO to the ABS module DTC Chart. Go to  OB2.
  2. OB2: DETERMINE SELECTABLE DRIVE MODE CAPABILITY 
    • Press the Read Vehicle Information button to view the results of the modules communicating on the network.
    • Retrieve the continuous memory DTCs.
    • Is the vehicle equipped with an ATCM? 
      Yes No
      Go to  OB13. For Aviator, Go to  OB7.
      For Corsair, Go to  OB7.
      For Escape, Go to  OB7.
      For Expedition without an ATCM and with a column mounted selector lever, Go to  OB3.
      For Expedition without an ATCM and with a GSM, Go to  OB17.
      For Explorer, Go to  OB7.
      For F-150, Go to  OB5.
      For F-Series Super Duty with a 6.2L or 7.3L engine, Go to  OB5.
      For F-Series Super Duty with a 6.7L engine, Go to  OB3.
      For Navigator without an ATCM and with a GSM, Go to  OB17.
      For all others, Go to  OB10.
  3. OB3: VERIFY THE TCM COMMUNICATES ON THE NETWORK 
    • Press the Read Vehicle Information button to view the results of the modules communicating on the network.
    • Retrieve the continuous memory DTCs.
    • Does the TCM pass the Network Test? 
      Yes No
      Go to  OB4. REFER to the Module Communications Network article to diagnose the TCM does not respond to the diagnostic scan tool.
  4. OB4: CHECK FOR TCM DTCS 

    Carry out the TCM self-test.

    • Are any DTCs present in the TCM? 
      Yes No
      DIAGNOSE all TCM DTCs before diagnosing the selectable drive mode switch. REFER to the appropriate procedure in the Automatic Transmission article. Go to  OB10.
  5. OB5: VERIFY THE PCM COMMUNICATES ON THE NETWORK 
    • Press the Read Vehicle Information button to view the results of the modules communicating on the network.
    • Retrieve the continuous memory DTCs.
    • Does the PCM pass the Network Test? 
      Yes No
      Go to  OB6. REFER to the Module Communications Network article to diagnose the PCM does not respond to the diagnostic scan tool.
  6. OB6: CHECK FOR PCM DTCS 

    Carry out the PCM KOEO self-test.

    • Are any DTCs present in the PCM? 
      Yes No
      DIAGNOSE all PCM DTCs before diagnosing the selectable drive mode switch. REFER to the appropriate procedure in the Electronic Engine Controls article. Go to  OB10.
  7. OB7: CHECK THE DRIVE MODE SWITCH GROUND CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Ignition ON, engine OFF.
    • Measure the resistance between:
      (+) (-)
      GND Ground
    • Measure the resistance between:
      (+) Drive Mode Switch Connector, Harness Side (-)
      GND Ground
    • Is the resistance less than 3 ohms? 
      Yes No
      Go to  OB8. REPAIR the circuit.
  8. OB8: CHECK THE DRIVE MODE CIRCUIT FOR AN OPEN 
    • Measure the resistance between:
      (+) (-) FCIM_B Connector, Harness Side
      DRV_ASST DRV_ASST
    • Measure the resistance between:
      (+) (-) FCIM_A Connector, Harness Side
      DRV_ASST DRV_ASST
    • Measure the resistance between:
      (+) (-) HVAC_A Module Connector, Harness Side
      SDM SDM
    • Measure the resistance between:
      (+) Drive Mode Switch Connector, Harness Side (-) HVAC_B Module Connector, Harness Side
      SDM DWN-RT SDM DWN-RT
      SDM UP-LT SDM UP-LT
    • Is the resistance less than 3 ohms? 
      Yes No
      Go to  OB9. REPAIR the circuit.
  9. OB9: CHECK THE DRIVE MODE CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
      (+) (-)
      DRV_ASST Ground
      SDM Ground
    • Measure the resistance between:
      (+) Drive Mode Switch Connector, Harness Side (-)
      SDM DWN-RT Ground
      SDM UP-LT Ground
    • Is the resistance greater than 10, 000 ohms? 
      Yes No
      INSTALL a new HVAC module.
      CHECK OASIS for any 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 services articles address this concern, INSTALL a new HVAC. REFER to the appropriate Cimate Control System General Information article.      		 REPAIR the circuit.
  10. OB10: CHECK FOR VOLTAGE TO THE TOW-HAUL/OVERDRIVE SWITCH 
    • Ignition OFF.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) Column Shifter Connector, Harness Side (-)
      SDM-V Ground
    • Measure the voltage between:
      (+) Floor Shifter Assembly Connector, Harness Side (-)
      SDM-V Ground
    • Measure the voltage between:
      (+) OD Connector, Harness Side (-)
      IGN START/RUN Ground
    • Is the voltage above 11 volts? 
      Yes No
      Go to  OB11. REPAIR the circuit.
      VERIFY BCM fuse 35 (5A) is OK.
      If the fuse is OK, REPAIR the circuit.
      If the fuse is not OK, REFER to the the OEM Electrical Wiring Diagrams Introduction article to determine to cause of the circuit short.
  11. OB11: CHECK THE TOW-HAUL/OVERDRIVE CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Measure the resistance between:
  12. OB12: CHECK THE TOW-HAUL/OVERDRIVE CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
      (+) Column Shifter Connector, Harness Side (-)
      SDM Ground
    • Measure the resistance between:
      (+) Floor Shifter Assembly Connector, Harness Side (-)
      SDM Ground
    • Measure the resistance between:
      (+) OD Connector, Harness Side (-)
      SDM Ground
    • Is the resistance greater than 10, 000 ohms? 
      Yes No
      CHECK OASIS for any 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 column shifter assembly, the overdrive cancel switch is part of the shifter assembly. REFER to the Automatic Transmission External Controls article.      		 REPAIR the circuit.
  13. OB13: CHECK THE ABS MODULE DTCS 
    • Ignition ON, engine OFF.

      Carry out the ABS self-test.

    • Retrieve and record all ABS module DTCs.
    • Is DTC U0138:xx or U0439:xx present in the ABS module? 
      Yes No
      GO to PINPOINT TEST BM . Go to  OB14.
  14. OB14: CHECK FOR ATCM DTCS 
    • Ignition ON, engine OFF.
    • Using a diagnostic scan tool, carry out the ATCM self-test.
    • Are any DTCs present in the ATCM? 
      Yes No
      If the ATCM does not communicate with the diagnostic scan tool, REFER to the Module Communications Network article.
      If the ATCM communicates with the diagnostic scan tool, DIAGNOSE all ATCM DTCs before diagnosing the selectable drive mode switch. REFER to the Four-Wheel Drive Systems article.      		 Go to  OB15.
  15. OB15: CHECK THE VOLTAGE TO THE ATCM 
    • Ignition OFF.
    • Measure the voltage between:
      (+) Traction Control Switch Connector, Harness Side (-)
      B+ Ground
    • Measure the voltage between:
      (+) ATCM Connector, Harness Side (-)
      B+ Ground
    • Is the voltage greater than 11 volts? 
      Yes No
      Go to  OB16. VERIFY all ATCM related fuses in the BJB are OK.
      REFER to the Fuse and Relay Location wiring diagrams for fusing information.
      If the fuses are OK, REPAIR the circuit.
      If the fuses are not OK, REFER to the the OEM Electrical Wiring Diagrams Introduction article to locate the cause of the circuit short.
  16. OB16: CHECK THE ATCM GROUND CIRCUIT FOR AN OPEN 
    • Measure the resistance between:
      (+) Traction Control Switch Connector, Harness Side (-)
      GND Ground
    • Measure the resistance between:
      (+) ATCM Connector, Harness Side (-)
      GND Ground
    • Is the resistance less than 3 ohms? 
      Yes No
      CHECK OASIS for any 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 ATCM. REFER to the the Four-Wheel Drive article.      		 REPAIR the circuit.
  17. OB17: CHECK THE ABS MODULE DTCS 
    • Ignition OFF.
    • Ignition ON, engine OFF.

      Carry out the ABS self-test.

    • Retrieve and record all ABS module DTCs.
    • Is DTC U0103:xx or U0404:xx present in the ABS module? 
      Yes No
      GO to PINPOINT TEST AV . Go to  OB18.
  18. OB18: CHECK FOR GSM DTCS 
    • Ignition ON, engine OFF.

      Carry out the GSM self-test.

    • Are any DTCs present in the GSM? 
      Yes No
      If the GSM does not communicate with the diagnostic scan tool, REFER to the Module Communications Network article.
      If the GSM communicates with the diagnostic scan tool, DIAGNOSE all GSM DTCs before diagnosing the selectable drive mode switch. REFER to the Automatic Transmission External Controls article.      		 Go to  OB19.
  19. OB19: CHECK THE SDM CIRCUIT FOR A SHORT TO GROUND 
    • Ignition OFF.
    • GSM connector disconnected. (C2503)
    • TCM connector disconnected.
    • Measure the resistance between:
      (+) GSM (C2503) Connector, Harness Side (-)
      SDM Ground
    • Is the resistance less than 3 ohms? 
      Yes No
      Go to  OB20. REPAIR the circuit.
  20. OB20: CHECK THE SDM CIRCUIT FOR AN OPEN 
    • Measure the resistance between:
      (+) GSM (C2503) Connector, Harness Side (-) TCM Connector, Harness Side
      SDM SDM
    • Is the resistance less than 3 ohms? 
      Yes No
      Go to  OB21. REPAIR the circuit.
  21. OB21: CHECK THE SDM CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition OFF.
    • TCM connector connected. Make sure the connector seats and latches correctly.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
      (+) GSM (C2503) Connector, Harness Side (-)
      SDM Ground
    • Is any voltage present? 
      Yes No
      REPAIR the circuit. CHECK OASIS for any 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 GSM. REFER to the the Automatic Transmission External Controls article.
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