1997 Mercedes-Benz SL320 Traction Control Switch Replacement Cost

Traction control is a system that works in conjunction with the anti lock brake system and engine management system. As it sounds, traction control creates safer driving environment by preventing wheel spin due to over acceleration or high lateral acceleration. More advanced traction control systems will incorporate components of the transfer case and differential(s) to assist in directing power to the appropriate wheels when needed. Many vehicles have a switch to turn off the traction control system, which allows for difficult maneuvering of the vehicle in situations where traction control may limit the vehicle's abilities.

The traction control system uses the anti lock brake control module to access the wheel speed sensors. When the ABS control module notes that the wheels are moving at different speeds, or that one or more wheels are turning while the others are not, the traction control system will use the anti lock brake system actuator to slow the wheels without traction, and release the wheels that are sliding. Further, most traction control systems will access the engine control module to decrease engine power to prevent further wheel slip or skidding. Advanced systems will use the transfer case and differentials to transfer power to the front or back of the vehicle or to the tires with the most traction. When the traction control switch is deactivated, these functions are either not performed, or are performed to a much lesser degree. In many cases, this may also disable the anti lock braking system (ABS).

Since the traction control system is thoroughly integrated into the ABS system, any malfunction of the traction control system will cause both the traction control system and the anti lock braking system to be disabled. However, the traction control switch failing may cause no symptoms at all. In the event that traction control needs to be disabled, the switch would simply not function. This would leave the traction control and anti lock braking systems active. This is generally the case, but note that if the traction control system is disabled for any other reason, the vehicle may need to be turned off and restarted to enable the traction control system when the switch is not functioning.

If the traction control switch does not cause the traction control system and anti lock brake system to deactivate, there is no harm in leaving the switch unrepaired. However, if these safety systems fail as a result of the traction control switch failing, the vehicle will perform drastically different in emergency situations and poor weather, so the added safety that the driver is accustomed to will not exist. In any case where these two safety system warning lights illuminate, have the vehicle serviced immediately.

Traction control switches are widely unused, and are typically not subject to abuse except for beverage spills. This being the case, a traction control switch failure is considered rare. However, this rarity should not imply longevity of the switch since failure of this small component can occur at any time, whether new or old.

Diagnosing the traction control switch is simple. The first thing any technician will do when the traction control warning lamp is active is to press and hold the traction control switch to determine if the system is just turned off. If this does nothing, further diagnostics will be performed, but when other components show no faults, the switch may be suspected. Testing the switch will involve removing the switch, leaving it connected electronically, and back probing the connector to determine continuity when pressed and released. If there is no continuity in the switch when pressed, the switch will be replaced.

Replacement will require removal of the switch from the panel it is mounted to. This may mean removing the trim panel to access hidden mounting fasteners or simple popping the switch out of its housing with a non-marring interior pry tool. Once replaced, any trim panel can be reinstalled, and the switch will be pressed to prove the customer complaint is resolved.

RepairPal is a strong advocate for diagnosis. It is very easy to absorb excess costs by replacing parts without testing them for failure. The first step that an owner can take is to turn off and restart the vehicle to see if the warning lamp turns off, followed by holding the traction control switch for several seconds. If neither works, diagnosis should be performed prior to replacing any components.

Not all vehicles will have a traction control switch, and those that do are not meant to be driven with the traction control permanently turned off. This creates a hazardous situation, and removes added safety components that have such a good track record that they are considered standard equipment on nearly all vehicles. For the sake of safety, only disable the traction control system when absolutely necessary or when driving off-road.

Diagnosing the traction control switch will likely not help locate the issue with the traction control system, but in the rare occasion that the traction control switch is the issue, may DIY mechanics with a multimeter can handle this repair quite easily. This is one of the easier component replacements, so there should be no real issue with removal and installation when the part is known to be faulty.