4X4 Control Module Symptom Chart

WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

Symptom Chart

Condition	Possible Sources	Action
The concern is unverifiable; no DTCs	The concern description is inaccurate	Go to Pinpoint Test A .
The transfer case makes noise	Tire inflation pressure Tire and wheel size	MAKE SURE all tires and wheels are the same size and brand, and the inflation pressures are correct.
	Fluid level	FILL with the correct type and amount of lubricant. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
	Internal components	OPERATE the vehicle in all transaxle gears. If there is noise in the transaxle in NEUTRAL, or in some gears and not in others, REMOVE and REPAIR the transaxle. REFER to AUTOMATIC TRANSAXLE/TRANSMISSION - CD4E article for automatic transaxle, AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) article for the electronically controlled continuously variable transmission (ECVT), or MANUAL TRANSAXLE/TRANSMISSION article for manual transaxle. If there is noise in all gears, INSTALL a new transfer case. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
Leaking fluid from the transfer case vent	Transfer case	DRAIN the fluid to the correct level. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
	Vent tube	REPAIR or INSTALL a new vent. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
Leaking automatic transmission fluid	Transfer case driven gear seal	INSTALL a new transfer case driven gear seal. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
Leaking gear lubricant from the seals	The vent is plugged	INSTALL a new vent. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
	Damaged seals	For automatic transaxle, INSTALL new seals. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article. For manual transaxle, INSTALL a new transfer case. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
No communication with the 4X4 control module	Smart junction box (SJB) fuse(s): 18 (10A) 35 (5A) 4X4 control module Circuitry	REFER to MODULE COMMUNICATIONS NETWORK article.
4X4 control module battery voltage is high or low	Concern with voltage regulator or generator SJB fuse 18 (10A) Intermittent open power circuit Relay failure inside 4X4 control module	Go to Pinpoint Test B .
4X4 control module received no/invalid data from PCM	Invalid data received from PCM Data out of range	Go to Pinpoint Test C .
4X4 control module received no/invalid data from ABS module	Invalid data received from the ABS module Data out of range	Go to Pinpoint Test D .
Controller area network (CAN) communications bus fault	CAN bus fault PCM fault ABS fault 4X4 control module	Go to Pinpoint Test E .
Vehicle has no or inadequate torque at rear wheels	Rear axle	REFER to REAR DRIVE AXLE/DIFFERENTIAL article.
	Tire/wheels Active torque coupling SJB fuse(s): 18 (10A) 35 (5A) 4X4 control module Circuitry	Go to Pinpoint Test F .
The 4-wheel drive (4WD) indicator does not operate correctly	Instrument cluster (IC) 4X4 control module Circuitry	Go to Pinpoint Test G .
Vehicle binds in a turn or resists turning	4X4 control module Active torque coupling Circuitry	Go to Pinpoint Test H .
Tire/axle out of acceptable range	Wheels/tires Wheel speed sensors ABS module 4X4 control module	Go to Pinpoint Test I .
Vehicle pulsates or shudders in a straight line	4X4 control module Active torque coupling Circuitry	Go to Pinpoint Test H .