TCS light always on????

TCS OFF light is always on, I press the TCS switch and it will not turn system on, Why would this be

Is your ABS light on the LH side of the IP also on?

If so, one of the front wheel cartridge bearing/speed sensors is very likely flaky or NOK.

Inspecting the wiring on the lower control arms out to the sensor(s) also holds merit as a damaged harness can cause the exact same symptoms.