Symptom Chart

WARNING: This page is about a different car, the 2004 Ford Explorer Sport Trac. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Refer to SYSTEM WIRING DIAGRAMS for connector numbers stated in the Pinpoint Tests.

DIAGNOSTIC REFERENCE

Condition	Possible Sources	Action
No communication with the anti-lock brake system (ABS) module	Battery junction box (BJB) fuse 16(50A) Central junction box (CJB) fuse 35 (5A) Ignition switch position Diagnostic tool Circuitry ABS module	go to PINPOINT TEST A .
Loss of sensor signal during vehicle deceleration or sensor signal drops out at low speed	Wheel speed sensor indicator Wheel speed sensor mounting Sensor output is weak Air gap	go to PINPOINT TEST D .
Unwarranted ABS activity	Wheel speed sensor indicator Circuitry Air gap Wheel speed sensor	go to PINPOINT TEST D .
Maladjusted rear brakes or "grabby" brake shoe or pad linings	Rear brake adjustment Linings	REFER to BRAKE SYSTEM-GENERAL INFORMATION .
Base brake mechanical concern for wheels lockup	Rear brake shoe linings Wheel cylinder Rear brakes Parking brake Rear axle seal	REFER to BRAKE SYSTEM-GENERAL INFORMATION . REFER to DISC & DRUM . REFER to DRIVELINE SYSTEM-GENERAL INFORMATION .
Base brake hydraulic concern (soft pedal)	Brake line or hose, fitting, master cylinder, wheel cylinder or caliper Air in brake system Hydraulic control unit (HCU)	REFER to BRAKE SYSTEM-GENERAL INFORMATION .
Base brake mechanical concern (hard pedal)	Vacuum boost Wheel cylinder or caliper Brake line or hose Hydraulic control unit (HCU)	REFER to BRAKE SYSTEM-GENERAL INFORMATION .
Base brake hydraulic concern during medium/hard brake application	Brake line or hose, fitting, master cylinder, wheel cylinder or caliper Air in brake system	REFER to BRAKE SYSTEM-GENERAL INFORMATION .
Base brake mechanical concern during medium/hard brake application	Vacuum boost Wheel cylinder or caliper Brake line or hose Brake shoe or pad linings	REFER to BRAKE SYSTEM-GENERAL INFORMATION .
Base brake mechanical concern for vehicle pulls	Rear brake Caliper Brake pad or shoe wear	REFER to BRAKE SYSTEM-GENERAL INFORMATION .
Base brake hydraulic concern for vehicle pulls	Brake line or hose	REFER to BRAKE SYSTEM-GENERAL INFORMATION .
One wheel locks up; no DTCs recorded	Base brake Dump valve ISO valve	REFER to BRAKE SYSTEM-GENERAL INFORMATION . INSTALL a new HCU. REFER to HYDRAULIC CONTROL UNIT .
The yellow ABS warning indicator does not self-check	Bulb Circuitry Instrument cluster Anti-lock brake system (ABS) module	go to PINPOINT TEST E .
Soft or excessive brake pedal	Brake line or hose, fitting, master cylinder, wheel cylinder, wheel cylinder or caliper Air in brake system Hydraulic control unit (HCU)	BRAKE SYSTEM-GENERAL INFORMATION .
Yellow ABS light always on, no DTC	Bulb Circuitry Anti-lock brake system (ABS) module Instrument cluster	go to PINPOINT TEST H .