Traction control light is on

What this usually means

First, sort out what the light is doing. Flickering briefly while you accelerate on a wet or icy road means traction control is working — that’s normal. A light that stays on steadily means the system has shut off, either because you pressed the TC-off button or because it detected a fault. Traction control doesn’t have its own set of wheel sensors: it borrows the ABS wheel speed sensors and hydraulics to detect and correct wheelspin. That’s why a single failed sensor so often lights the traction control and ABS lamps together — and why the fix for one is usually the fix for both. A traction light alone, with ABS still happy, tends to point at an engine-side input instead, since the system also cuts engine torque to control spin.

Most likely causes

• high
  Failed wheel speed sensorThe most common culprit, shared with the ABS system. One bad sensor blinds the system to that wheel’s speed, so it disables itself — typically lighting both the traction and ABS lamps.
• medium
  ABS system fault disabling traction controlAny fault that takes ABS offline — module, pump, wiring — takes traction control down with it, because TC applies its corrections through the ABS hydraulics.
• medium
  Damaged sensor wiring or tone ringChafed wheel-sensor wiring or a corroded tone ring produces a garbled signal with the same result as a dead sensor. Intermittent lights that come and go usually live here.
• low
  Engine or throttle faultBecause the system trims engine power to manage wheelspin, some throttle and engine faults disable it and light the lamp — usually with a check engine light alongside. On these, the engine code is the lead to follow.
• low
  Steering angle sensor faultStability control needs to know where you’re steering. A sensor that’s failed or lost calibration — sometimes after an alignment or battery disconnect — can trip the light, and on some cars a simple recalibration clears it.

How urgent is it?

Typical fix & cost

First step is the button — more of these “faults” than anyone admits are a knee bumping the TC-off switch. After that, a scan of the ABS system usually names a wheel speed sensor or wiring fault, which is a modest repair that restores traction control and ABS in one go. Engine-side triggers get fixed through the engine code, and a steering angle sensor may just need recalibration.

Common questions

Related OBD-II codes

If your car has stored a trouble code, these often come with this symptom:

Related symptoms

General guidance, not a substitute for a hands-on inspection. Cost ranges are broad reference ranges, not quotes. For safety-related issues, have the car inspected before driving.