Pinpoint Test I: Neutral Tow Functional Test
Four Wheel Drive (4WD) Systems - Electronic Shift
Pinpoint Tests
Pinpoint Test I: Neutral Tow Functional Test
Refer to Wiring Diagram Set 34, Four-Wheel Drive System for schematic and connector information. Diagrams By Number
Normal Operation
Neutral tow is a dealer installed option that allows the vehicle to be towed without damaging the transmission. Neutral tow operates by disengaging the transmission from the rear differential.
This pinpoint test is intended to diagnose the following:
- Neutral tow indicator
- Controller Area Network (CAN) circuits
- Smart Junction Box (SJB)
- Transmission Range (TR) sensor
- Door ajar switch
- Ignition switch/circuitry
PINPOINT TEST I: NEUTRAL TOW FUNCTIONAL TEST
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I1 CHECK THE NEUTRAL TOW INDICATOR PROVE OUT
- Ignition ON.
- Ignition OFF.
- Does the neutral tow indicator prove-out?
Yes
GO to I2.
No
GO to I7.
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I2 CHECK NEUTRAL TOW ACTIVATION
- Activate neutral tow:
- make sure that the Four-Wheel Drive (4WD) system is in 2-Wheel Drive (2WD) mode.
- press and hold the brake pedal.
- transmission in N (NEUTRAL).
- key in OFF position.
- wait 5 seconds.
- Does neutral tow activate?
Yes
GO to I3.
No
GO to I9.
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I3 CHECK FOR NEUTRAL TOW TIME-OUT
- Close the driver door.
- Monitor the neutral tow indicator.
- Does the indicator turn off after 20 seconds?
Yes
GO to I4.
No
CHECK the door ajar switch/SJB for faults. REFER to Interior Lighting Testing and Inspection.
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I4 CHECK NEUTRAL TOW INDICATION
- Open the driver door.
- Monitor the neutral tow indicator.
- Does the neutral tow indicator illuminate?
Yes
GO to I5.
No
CHECK the door ajar switch/SJB for faults. REFER to Interior Lighting Testing and Inspection.
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I5 CHECK NEUTRAL DEACTIVATION BY THE IGNITION SWITCH
- Ignition ON.
- Does neutral tow deactivate?
Yes
GO to I6.
No
GO to I9.
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I6 CHECK NEUTRAL TOW REACTIVATION
- Reactivate neutral tow:
- make sure that the 4WD system is in 2WD mode.
- press and hold the brake pedal.
- transmission in N (NEUTRAL).
- key in OFF position.
- wait 5 seconds.
- Deactivate neutral tow by shifting the transmission out of NEUTRAL.
- Does neutral tow reactivate then deactivate?
Yes
The neutral tow system is functional.
No
GO to I10.
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I7 CHECK NEUTRAL TOW SYSTEM INSTALLATION
- Verify that all neutral tow system components are installed correctly.
- Are all neutral tow system components installed correctly?
Yes
GO to I8.
No
INSTALL the neutral tow system components as necessary. REPEAT the functional test.
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I8 CHECK THE NEUTRAL TOW INDICATOR OPERATION
- Connect: DataLogger - 4X4 Control Module.
- Follow the scan tool directions to activate the neutral tow system.
- Monitor the neutral tow indicator.
- Key ON, then key OFF.
- Does the neutral tow indicator prove-out correctly?
Yes
GO to I2.
No
CHECK and REPAIR the neutral tow system wiring as necessary. REPEAT the functional test.
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I9 CHECK THE TRANSFER CASE SHIFT MOTOR OPERATION BY ACTIVATING 4X4 LOW
- Ignition ON.
- Monitor the Instrument Cluster (IC) 4X4 LOW indicator:
- vehicle stationary.
- shift the transmission to N (Neutral).
- select 4L.
- wait for the 4X4 LOW indicator to illuminate in the IC indicating that the shift is complete.
- Does the 4X4 LOW indicator illuminate?
Yes
GO to I10.
No
GO to Pinpoint Test D. Pinpoint Test D: The Vehicle Does Not Shift Between Four-Wheel Drive (4WD) High and Four-Wheel Drive (4WD) Low Correctly
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I10 CHECK THE NEUTRAL SAFETY SWITCH (NTRL_SW) AND IGNITION STATE PIDs
- Connect the scan tool.
- Ignition OFF.
- Enter the following diagnostic mode on the scan tool: DataLogger - 4X4 Control Module.
- A. Monitor the NTRL_SW status PID while shifting the transmission through gear ranges.
- B. Monitor the ignition state PID.
- Ignition Switch - Off/Unlock Position (IGN_O/U)
- ACC Position (IGN_A)
- Start Position 3 (IGN_S)
- Ignition Switch - Run/Start Position (IGN_R/S)
- Ignition Switch - Run Position (IGN_R)
- A. Does the NTRL_SW PID indicate NEUTRAL when the transmission is shifted to NEUTRAL?
B. Does the ignition state PID indicate OFF?
Yes
If both PIDs are accurate, INSTALL a new 4X4 control module. REFER to 4X4 Control Module Service and Repair. REPEAT the functional test.
No
A. REFER to Automatic Transmission - 5R44E and 5R55E Testing and Inspection for further diagnosis of the neutral safety switch.
B. REFER to Steering Column Switches Testing and Inspection for further diagnosis of the ignition switch.
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