Symptom Chart - Four-Wheel Drive (4WD) System

WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

4WD SYSTEM SYMPTOM CHART

Condition	Possible Sources	Action
No communication with the TCCM	Scan tool DLC TCCM Wiring, terminals or connectors	REFER to MODULE COMMUNICATIONS NETWORK .
The 4WD indicators do not operate correctly	Wiring, terminals or connectors 4WD system fault IPC TCCM	GO to PINPOINT TEST A .
The vehicle does not shift between 2H and 4H modes correctly	Wiring, terminals or connectors MSS Transfer case Transfer case synchronization clutch IWEs IWE solenoid TCCM Front axle assembly	GO to PINPOINT TEST B .
The vehicle does not shift between 4H and 4L modes correctly	TR Transmission drag torque ABS wheel speed inputs HS-CAN	GO to PINPOINT TEST C .
The 4WD does not engage at speed correctly	Transfer case synchronization clutch Transfer case TCCM Front axle assembly Wiring, terminals or connectors	GO to PINPOINT TEST G .
The front axle does not engage/disengage correctly	MSS IWEs IWE solenoid Transfer case Vacuum leaks Front axle assembly TCCM Wiring, terminals or connectors Fuses	GO to PINPOINT TEST D .
The transfer case jumps out of gear	IWE vent line(s) MSS Transfer case	GO to PINPOINT TEST E .
Unable to duplicate customer concern	4WD system and/or related components	CARRY OUT the ESOF Functional Test. GO to PINPOINT TEST I .
Rear wheels binding when turning corners with the MSS in 2WD or OFF	Wiring, terminals or connectors ELD field coil Differential	Go to PINPOINT TEST AD in Electronic Locking Differential (ELD) System, Diagnosis and Testing.
Off-road mode is inoperative Wiring, terminals or connectors	Off-road mode switch TCCM	GO to PINPOINT TEST K .
Off-road mode switch indicator is inoperative	Wiring, terminals or connectors Off-road mode switch TCCM	GO to PINPOINT TEST J .
Unable to achieve flat tow (neutral tow) mode	Wiring, terminals or connectors HS-CAN IPC TCCM Door ajar switch Ignition switch	Go to PINPOINT TEST AH in Electronic Locking Differential (ELD) System, Diagnosis and Testing.