Pinpoint Test AH: Neutral Flat Tow Functional Test

Electronic Locking Differential (ELD) System

Pinpoint Test AH: Neutral Flat Tow Functional Test

Normal Operation

Neutral flat tow operates by shifting the transfer case shift motor into the NEUTRAL position, locking the transfer case in NEUTRAL. The TCCM (Transfer Case Control Module) sends the transfer case shift motor NEUTRAL position status to the IPC (Instrument Panel Cluster) over the HS-CAN (High Speed Controller Area Network).

This pinpoint test is intended to diagnose the following:

- IPC (Instrument Panel Cluster)

- TCCM (Transfer Case Control Module)

- TR (Transmission Range) sensor from PCM

- Ignition switch

PINPOINT TEST AH : NEUTRAL FLAT TOW FUNCTIONAL TEST

WARNING: Shifting the transfer case to its neutral position for neutral flat towing may allow the vehicle to be able to roll even if the transmission is in park (P). Make sure the foot brake is depressed and the vehicle is in a secure and safe position while the transfer case is being shifted to its neutral position. Failure to follow this instruction may result in serious personal injury.
WARNING: Do not disconnect the battery during neutral flat towing. Doing so will prevent the transfer case from shifting properly and may allow the vehicle to roll even if the transmission is in park (P). Failure to follow this instruction may result in serious personal injury.
NOTICE: 2WD (2-Wheel Drive) vehicles cannot be towed with any wheels on the ground as vehicle or transmission damage may occur.
NOTICE: Failing to put the transfer case in its NEUTRAL position will damage vehicle components.
NOTE:
4WD (Four-Wheel Drive) vehicles can only be flat towed with all wheels on the ground by placing the transfer case in its NEUTRAL position.

AH1 CHECK NEUTRAL FLAT TOW ACTIVATION AND DEACTIVATION

- Activate neutral flat tow. Refer to Neutral Flat Tow Activation and Deactivation Neutral Flat Tow Activation and Deactivation.

Does the IPC (Instrument Panel Cluster) indicate neutral flat tow is activated?

Yes
RETURN the vehicle to the customer. ADVISE the customer about the correct Neutral Flat Tow Activation and Deactivation procedure.
No
GO to AH2.

AH2 CHECK NEUTRAL FLAT TOW ACTIVATION WHILE MONITORING THE TCCM (Transfer Case Control Module) 4WD MODES (4WD_MODES) PID

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: DataLogger- TCCM (Transfer Case Control Module).

- Monitor the 4WD_MODES PID.

Does the PID indicate NEUTRAL?

Yes
REFER to Instrument Panel, Gauges and Warning Indicators to diagnose IPC (Instrument Panel Cluster) faults. After the repair is complete, CLEAR the DTCs. TEST the system for normal operation.
No
GO to AH3.

AH3 CHECK FOR TCCM (Transfer Case Control Module) DTCs

- Enter the following diagnostic mode on the scan tool: Self-Test- TCCM (Transfer Case Control Module).

Are any DTCs present?

Yes
REFER to the TCCM (Transfer Case Control Module) DTC Chart Electronic Locking Differential (ELD) System. After the repair is complete, CLEAR the DTCs. TEST the system for normal operation.
No
GO to AH4.

AH4 CHECK TCCM (Transfer Case Control Module) BRAKE ON/OFF (4X4_BOO) PID

- Enter the following diagnostic mode on the scan tool: DataLogger- TCCM (Transfer Case Control Module).

- Monitor the 4X4_BOO PID while pressing the brake pedal.

Does the PID agree with the brake pedal position?

Yes
GO to AH5.
No
REFER to Lighting and Horns to diagnose stoplamp system faults. After the repair is complete, CLEAR the DTCs. TEST the system for normal operation.

AH5 CHECK THE TCCM (Transfer Case Control Module) IGNITION POSITION (KEY_POS_4X4) PID

- Enter the following diagnostic mode on the scan tool: DataLogger- TCCM (Transfer Case Control Module).

- Monitor the KEY_POS_4X4 PID with the ignition in the ON position.

Does the PID indicate Ignition On?

Yes
GO to AH6.
No
REFER to Steering Column for further diagnosis of the ignition switch.

AH6 CHECK THE TCCM (Transfer Case Control Module) NEUTRAL INDICATOR (NEUTRAL) PID

- Enter the following diagnostic mode on the scan tool: DataLogger- TCCM (Transfer Case Control Module).

- Monitor the NEUTRAL PID with the gear selector in neutral position.

Does the PID indicate TRUE?

Yes
For vehicles equipped with the ESOF (Electronic Shift-On-The-Fly) system, GO to Pinpoint Test B Pinpoint Test B: The Vehicle Does Not Shift Between 2H and 4H Correctly and Grinding Noise Heard During 4WD engagement to diagnose the transfer case shift motor.

For vehicles equipped with the 2-speed torque-on-demand system, GO to Pinpoint Test P Pinpoint Test P: The Vehicle Does Not Shift Between 4H (4X4) and 4L (4X4 Low) Modes Correctly to diagnose the transfer case shift motor.
No
REFER to Automatic Transmission/Transaxle &/or Transmission Control Systems for diagnosis of the TR (Transmission Range) sensor.