Traction Control

Traction Control





Components
1. Separation valve, normally open
2. Electronic shuttle valve, normally closed
3. Hydraulic pump
4. Outlet valve, normally closed
5. Inlet valve, normally open
6. Pressure equalizer
7. By-pass valve
8. Non-return valve.

Traction control is integrated in the steering wheel bracket.
The system is mainly designed to assist with moving off on slippery surfaces at speeds up to approximately 60 km/h. Traction control has only a very limited effect at speeds over 60 km/h. The traction control function is always engaged when the ignition is switched on. The function can be disengaged (model years 1999-2002 only) using the STC/DSTC switch, which is located on the lower section of the Climate Control Module (CCM).
If the Brake Control Module (BCM) registers, via the front wheel sensors, that one of the driven wheels is spinning faster than the other, the separation valve (1) closes and the hydraulic pump (3) starts so that the brake fluid is pumped to the brake caliper of the slipping wheel. Pressure builds up in the brake circuit and the brakes are applied as much as required so that the drive force is distributed between the driven wheels. The wheel which has the best traction receives the most driven force against the surface. This process is independent of engine output.
On cars with traction control, the Brake Control Module (BCM) continually registers brake usage and calculates the temperatures of the front wheel brake discs. If traction control is engaged and the calculated temperature is too high (approximately 450°C), traction control cuts out and the wheel spin warning indicator lights (applies to model year 1999-2002). From model year 2003, the general warning lamp (yellow) lights, and a text is displayed in the combined instrument panel. A Diagnostic Trouble Code (DTC) is stored in the Brake Control Module (BCM). Traction control is blocked to prevent the brakes from overheating.
The light goes out once the calculated temperature falls below approximately 300°C and traction control is engaged again. However, the ABS function is always available. Information about the calculated temperature of the brake discs is in the Brake Control Module (BCM) as long as the 30-supply is connected. If the brake system has been used too hard, this may also cause high brake temperatures.