Symptom Chart

WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 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 present	The concern description is inaccurate	CARRY OUT the functional test. Go to Pinpoint Test A .
The power transfer unit (PTU) 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 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 or AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) article. If there is noise in all gears, INSTALL a new PTU. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
Leaking fluid from the PTU vent	PTU	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 gear lubricant from the seals	The vent is plugged	INSTALL a new vent. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
	Damaged seals	INSTALL new seals. REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
4X4 control module battery voltage is high or low	Concern with voltage regulator or generator Smart junction box (SJB) fuse 35 (10A) Intermittent open power circuit 4X4 control module internal power relay failure	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 .
High-speed controller area network (HS-CAN) communications bus fault	HS-CAN bus fault PCM fault ABS fault Instrument cluster (IC) 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.
	PTU mechanical failure	REFER to TRANSFER CASE - POWER TRANSFER UNIT (PTU) article.
	Tire/wheels Active torque coupling Smart junction box (SJB) fuse(s): 11 (10A) 35 (10A) 4X4 control module	Go to Pinpoint Test H .
	Circuitry	Go to Pinpoint Test F .
Vehicle binds in a turn or resists turning/pulsates or shudders in a straight line	Wheel/tire assembly(s)	REFER to WHEELS AND TIRES article.
	Brake system	REFER to BRAKE SYSTEM - GENERAL INFORMATION article.
	Wheel bearings	REFER to SUSPENSION SYSTEM - GENERAL INFORMATION article.
	Halfshafts	REFER to DRIVELINE SYSTEM - GENERAL INFORMATION article.
	Wheel speed sensor(s) ABS module	REFER to VEHICLE DYNAMIC SYSTEMS article.
	4X4 control module Active torque coupling Circuitry	Go to Pinpoint Test G .
Tire/axle out of acceptable operating range	Wheels/tires Wheel speed sensors ABS module 4X4 control module	Go to Pinpoint Test H .
Vehicle pulsates or shudders in a straight line	Brake system	REFER to BRAKE SYSTEM - GENERAL INFORMATION article.
	Wheel bearings	REFER to SUSPENSION SYSTEM - GENERAL INFORMATION article.
	Halfshafts	REFER to DRIVELINE SYSTEM - GENERAL INFORMATION article.
	4X4 control module Active torque coupling Circuitry Wheel/tire assembly(s) Wheel speed sensor(s) ABS module	Go to Pinpoint Test G .