Traction Control System

A traction control system shares components — traction control module, wheel speed sensors and electronic control module–with a vehicle’s anti-lock brake system. Common traction control problems occur with wheel speed sensors, high pressure accumulators and traction control system modules. A wiring problem or terminal corrosion will cause problems with interaction between the traction control system and the anti-lock brake system module.


Some drivers may find the intervention of traction control annoying, especially if they drive a performance vehicle. So most systems have a button or switch that allows the driver to temporarily deactivate traction control. When the system is disabled, a warning light will illuminate to remind the driver traction control is not available. The system will remain disabled until the driver pushes the TCS button again, or until the start of the next ignition cycle (the default mode for TCS is usually ON).

Note: Disabling traction control does not disable or affect the operation of the ABS system. ABS remains on all the time unless it has disabled itself due to an internal fault.

Most traction control systems only operate at speeds below 30 MPH because traction control usually isn’t necessary at higher speeds. Also, braking at higher speeds could have an adverse effect on vehicle handling and stability — unless traction control is also part of a total stability control system that monitors vehicle stability and handling at all speeds.


The traction control system has its own warning light and shares its internal self-diagnostics with the ABS system. If a fault occurs in any of the components that affect the operation of either system, one or both warning lights will come on and a diagnostic trouble code (DTC) will be set in the control module that corresponds to the fault(s).

If the TCS or ABS warning lights are on, one or both systems are usually disabled and will remain offline until the fault is diagnosed and repaired.

The procedure for reading and clearing TCS/ABS fault codes will vary depending on the vehicle model year and system. On older vehicles and some imports (Acura, for example), the TCS/ABS module has manual flash codes and no scan tool is needed. On most newer applications, though, a scan tool is needed.

TCS/ABS diagnostics requires a scan tool with software that can talk to the TCS/ABS module or body control module (depending on how the vehicle is wired). The scan tool must also be CAN-compliant if the vehicle is a newer one with a Controller Area Network (CAN).

On most applications, the TCS/ABS system will have a number of self-tests that can be run through the scan tool. This includes tests that operate the pump and tests for the TCS/ABS solenoids. Some of these tests may only be available with an OEM factory scan tool.


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