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Diagnosis and Testing > < 206-09B Anti-Lock Control - Traction Control|Specifications
Anti-Lock Control - Traction Control - Anti-Lock Control - Traction Control Focus 1999 (08/1998-12/2004)
Description and Operation

WARNING:
WARNING:Brake fluid contains polyglycol ethers and polyglycols. Avoid contact with the eyes. Wash hands thoroughly after handling. If brake fluid contacts the eyes, flush the eyes for 15 minutes with cold running water. Get medical attention if irritation persists. If taken internally, drink water and induce vomiting. Get medical attention immediately. Failure to follow these instructions may result in personal injury.

The anti-lock control - traction control is an expanded version of the anti-lock brake system (ABS). The system is integrated with the ABS and uses the same wheel speed sensors and a similar hydraulic control unit (HCU).

The hydraulic control unit has additional internal solenoid valves incorporated to enable control modulation of the wheel brake pressures.

The traction control system reduces spinning of the driving wheels; this can be achieved as a result of intervention through the engine management system and/or the brake.

Two traction control systems are available: brake traction control system (BTCS) for 1.4L and diesel engines, and full speed traction control (TCS) for 1.6L, 1.8L and 2.0L engines.

At speeds above 40km/h, only large amounts of wheel slip is controlled by the brake function (ie aquaplaning).

In order to avoid possible increased wear to the braking system, the ABS/TCS and BTCS systems calculate the brake pad temperature and if it becomes to high brake intervention is switched off until such times that the temperature has been reduced.

Brake Traction Control System (BTCS)

This system minimizes wheel slip on the driven axle to enhance traction at lower speeds and is achieved by controlled braking of the spinning driving wheel, when the grip at the driven wheels are different. It is an integral function of the ABS and cannot be switched off.

The BTCS system is only active at road speeds up to 85 km/h (53 mph). When the system is active the driver is made aware of the fact by the illumination of a warning indicator located in the instrument cluster.

The spinning wheel is braked by the ABS system.

This transfers a greater proportion of the engine torque through the differential to the other driven wheel, thereby increasing the utilization of the available traction control works at all speeds below 50 km/h.

Full Speed Traction Control (TCS)

This system controls wheel slip on the driven axle by a combination of engine torque reduction and brake control to enhance vehicle stability, steerability and traction at all vehicle speeds. The TCS function can be switched off and is controlled by a switch in the floor console.

If the ABS/TCS module registers that the driving wheels are spinning, the EEC V Powertrain Control Module (PCM) can be requested to reduce the engine torque via the standard corporate protocol (SCP) bus (ISO 9141.Ford). For additional information, refer to Section  303-14 Electronic Engine Controls.

The ABS/TCS module calculates the required engine torque during traction control and sends this request to the EEC V PCM.

The EEC V PCM then calculates the required ignition timing and the number of fuel injectors to be deactivated in order to achieve the required engine torque.

The advantage of the TCS system over the BTCS system are as follows:

  • reduce load on the braking system
  • reduced load on the powertrain
  • improved directional stability
  • improved steering
  • shorter reaction time
  • operates at all vehicle speeds

Diagnosis and Testing > < 206-09B Anti-Lock Control - Traction Control|Specifications