Vehicle Dynamic Systems: Overview Ford Focus I facelift

Normal Operation

When the brakes are pressed voltage is supplied from the brake switch to the generic electronic control module (GEM) to the brake lights.

Possible Causes

1. Fuse
2. Circuit open
3. Circuit shorted
4. Brake switch
5. GEM

The operating voltage required to supply the ABS module, hydraulic pump and isolation valves is in a range between 10 and 16 volts.

Voltage is supplied by the battery junction box (BJB) through circuit 30-CF13 (RD) (hot at all times), circuit 30-CF6 (RD) (hot at all times) and circuit 15-CF6A (GN/YE) (hot in run). Ground is provided through circuit 31-CF6 (BK).

Possible Causes

1. Charging system
2. Battery
3. Circuit open
4. ABS module

The operating voltage required to supply the ABS module, hydraulic pump and isolation valves is in a range between 10 and 16 volts.

Voltage is supplied by the battery junction box (BJB) through circuit 30-CF13 (RD) (hot at all times), circuit 30-CF6 (RD) (hot at all times) and circuit 15-CF6 (GN/YE) (hot in run). Ground is provided through circuit 31-CF6 (BK).

Possible Causes

1. Fuse
2. Circuit open
3. ABS module

The wheel speed sensors generate a signal that is sent to the anti-lock brake system (ABS) module. The wheel speed sensor circuitry connects to the ABS module through 2 wires and a connector at each wheel speed sensor. When the ignition switch is turned to the RUN position, the ABS carries out a self-test by sending out a reference voltage through the wheel speed sensor and its circuitry to determine if the speed sensors are functional

Possible Causes

1. Fuse
2. Circuit open
3. Circuit shorted
4. ABS module

The wheel speed sensors generate a signal that is sent to the anti-lock brake system (ABS) module that is proportional to wheel speed. The ABS module compares the wheel speed inputs from all wheel speed sensors to determine an impending lockup.

Possible Causes

1. Mismatched tire sizes
2. Wheel speed sensor ring
3. Wheel speed sensor
4. ABS module

The operating voltage required to supply the ABS module, hydraulic pump and isolation valves is in a range between 10 and 16 volts.

Possible Causes

1. Calibration failure
2. ABS module

The traction control switch (TCS) allows the driver to control the ON/OFF operation of the traction control system by pressing the switch for a minimum of one second, independent of the ABS function.

The TCS receives voltage from the ABS module on circuit 91S-CF54 (BK/WH).

Possible Causes

1. Circuit open
2. TCS
3. ABS module

The traction control switch (TCS) allows the driver to control the ON/OFF operation of the traction control system by pressing the switch for a minimum of one second, independent of the ABS function.

The traction control switch receives voltage from the ABS module on circuit 91S-CF54 (BK/WH).

Possible Causes

1. Circuit open
2. TCS
3. ABS module