Pinpoint Test J: Poor Vehicle Tracking During Anti-Lock Function

WARNING: This page is about a different car, the 2006 Mercury Montego, 2006 Ford Freestyle, and 2006 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.

J1 BLEED THE BRAKE SYSTEM
- Bleed the brake system using the diagnostic tool. Refer to BRAKE SYSTEM BLEEDING .
- Test drive the vehicle.
- Does the vehicle still track poorly?
Yes: GO to J2.

No: The brake system is operating correctly. The concern may have been caused by air in the hydraulic system or a sticky valve.
J2 CHECK THE ABS INLET VALVE (CLOSED POSITION)
- Connect the scan tool.
- Key in ON position.
- Raise and support the vehicle. Refer to JACKING & LIFTING .
- Rotate all the wheels to make sure they rotate freely (the transaxle must be in NEUTRAL).
- Trigger the ABS module LF INLET ON active command.
- Apply moderate brake pedal effort.
- Have an assistant attempt to rotate the LF wheel.
- Does the LF wheel rotate?
Yes: TRIGGER the LF INLET OFF active command. GO to J3.

No: INSTALL a new HCU. REFER to HYDRAULIC CONTROL UNIT (HCU) . TEST the system for normal operation.
J3 CHECK THE ABS INLET VALVE (OPEN POSITION)
- Apply moderate brake pedal effort.
- Have an assistant attempt to rotate the LF wheel.
- Does the LF wheel rotate?
Yes: INSTALL a new HCU. REFER to HYDRAULIC CONTROL UNIT (HCU) . TEST the system for normal operation.

No: GO to J4.
J4 CHECK THE ABS OUTPUT VALVE (OPEN POSITION)
- Apply moderate brake pedal effort.
- Trigger ABS module LF INLET ON active command.
- Trigger ABS module ABS POWER ON active command (turns on the pump motor) for 6 seconds. (The trigger must be pressed 3 times. Each press runs the pump for 2 seconds.)
- Trigger the ABS module LF OUTLET ON active command, then trigger the ABS module LF OUTLET OFF active command. Repeat 3 times.
- Have an assistant attempt to rotate the LF wheel.
- Does the LF wheel rotate?
Yes: TRIGGER all active commands OFF. GO to J5.

No: INSTALL a new HCU. REFER to HYDRAULIC CONTROL UNIT (HCU) . TEST the system for normal operation.
J5 CHECK ABS INLET AND OUTLET VALVE (CLOSED POSITION)
- Apply moderate brake pedal effort.
- Have an assistant attempt to rotate the LF wheel.
- Does the LF wheel rotate?
Yes: INSTALL a new HCU. REFER to HYDRAULIC CONTROL UNIT (HCU) . TEST the system for normal operation.

No: REPEAT this procedure (beginning with Step J2) for the RF, LR and RR wheels using the appropriate active commands. If no failure occurs the system is operating normally.