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Visual Inspection and Diagnostic Pre-checks

WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
Fig 1: All Terrain Control Module (ATCM) Connector End View (C3393)
G12751640Courtesy of FORD MOTOR CO.
Harness Side

Circuit Pin
B+ (Battery Positive Voltage) - SBP32 1 (VIOLET/RED)
GND (Ground) - GD216 4 (BLACK/VIOLET)
  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
    Diagnose 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. Go to  OB3.
  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 MODULE COMMUNICATIONS NETWORK (2 OF 2) 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 AUTOMATIC TRANSMISSION - 10R80 (1 OF 2) or AUTOMATIC TRANSMISSION - 10-SPEED AUTOMATIC TRANSMISSION - 10R80 (2 OF 2) . Go to  OB7.
  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 MODULE COMMUNICATIONS NETWORK (2 OF 2) 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 ELECTRONIC ENGINE CONTROLS - 3.5L ECOBOOST (272KW/370PS) . Go to  OB10.
  7. OB7: CHECK FOR VOLTAGE TO THE DRIVE MODE 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 (C2135) Connector, Harness Side (-)
      IGN START/RUN - CBP19 (BROWN/WHITE) - Pin 1 Ground
    • Is the voltage above 11 volts? 
    Yes No
    Go to  OB8. REPAIR the circuit.
  8. OB8: CHECK THE SELECTABLE DRIVE MODE CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Measure the resistance between:
      (+) Column Shifter Connector, Harness Side (-) TCM (C1822) Connector, Harness Side
      SDM SDM - CET34 - Pin 19
    • Measure the resistance between:
      (+) Floor Shifter Assembly Connector, Harness Side (-) PCM_B (C1915B) Connector, Harness Side
      SDM SDM
    • Measure the resistance between:
      (+) OD (C2135) Connector, Harness Side (-) TCM (C1822) Connector, Harness Side
      SDM - CET34 (BROWN/GREEN) - Pin 2 SDM - CET34 - Pin 19
    • Is the resistance less than 3 ohms? 
    Yes No
    Go to  OB9. REPAIR the circuit.
  9. OB9: CHECK THE SELECTABLE DRIVE MODE 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 (C2135) Connector, Harness Side (-)
      SDM - CET34 (BROWN/GREEN) - Pin 2 Ground
    • Is the resistance greater than 10, 000 ohms? 
    Yes No
    INSTALL a new column shifter assembly (the switch is part of the shifter assembly) or transmission range selector. REFER to the appropriate procedure AUTOMATIC TRANSMISSION EXTERNAL CONTROLS . REPAIR the circuit.
  10. OB10: CHECK FOR VOLTAGE TO THE TOW-HAUL SWITCH 
    • Ignition OFF.
    • Column Shifter connector disconnected. (if equipped)
    • Floor Shifter Assembly connector disconnected. (if equipped)
    • PCM_B connector disconnected. (C1915B)
    • Ignition ON, engine OFF.
      NOTE: Verify BCM fuse 35 (5A) is OK. If not OK, refer to the OEM WIRING DIAGRAMS to identify the cause of the circuit short.
    • 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
    • Is the voltage above 11 volts? 
    Yes No
    Go to  OB11. REPAIR the circuit.
  11. OB11: CHECK THE SELECTABLE DRIVE MODE CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Measure the resistance between:
      (+) Column Shifter Connector, Harness Side (-) PCM_B (C1915B) Connector, Harness Side
      SDM SDM
    • Measure the resistance between:
      (+) Floor Shifter Assembly Connector, Harness Side (-) PCM_B (C1915B) Connector, Harness Side
      SDM SDM
    • Is the resistance less than 3 ohms? 
    Yes No
    Go to  OB12. REPAIR the circuit.
  12. OB12: CHECK THE SELECTABLE DRIVE MODE CIRCUIT FOR AN OPEN 
    • Measure the resistance between:
      (+) Column Shifter Connector, Harness Side (-)
      SDM Ground
    • Measure the resistance between:
      (+) Floor Shifter Assembly Connector, Harness Side (-)
      SDM Ground
    • Is the resistance greater than 10, 000 ohms? 
    Yes No
    INSTALL a new floor shifter or column shifter assembly, the tow-haul switch is part of the shifter assembly. REFER to the appropriate procedure AUTOMATIC TRANSMISSION EXTERNAL CONTROLS . REPAIR the circuit.
  13. OB13: CHECK FOR ATCM DTCS 
    • Review the results from the previous network test.
    • Are any DTCs present in the ATCM? 
    Yes No
    DIAGNOSE all ATCM DTCs before diagnosing the selectable drive mode switch. REFER to FOUR-WHEEL DRIVE SYSTEMS . Go to  OB14.
  14. OB14 
    • Ignition OFF.
    • ATCM connector disconnected. (C3393)
    • Ignition ON, engine OFF.
      NOTE: Verify BCM fuse 19 (10A) is OK. If not OK, refer to the OEM WIRING DIAGRAMS to identify the cause of the circuit short.
    • Measure the voltage between:
      (+) ATCM (C3393) Connector, Harness Side (-)
      B+ - SBP32 (VIOLET/RED) - Pin 1 Ground
    • Is the voltage greater than 11 volts? 
    Yes No
    Go to  OB15. REPAIR the circuit.
  15. OB15 
    • Measure the resistance between:
      (+) ATCM (C3393) Connector, Harness Side (-)
      GND - GD216 (BLACK/VIOLET) - Pin 4 Ground
    • Is the resistance less than 3 ohms? 
    Yes No
    INSTALL a new ATCM.
    REFER to FOUR-WHEEL DRIVE SYSTEMS .    		 REPAIR the circuit.
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