Traction or stability control light

Traction or stability control light

If the light is flashing, you don't need to do anything except drive to match the conditions. It means the system is actively working right now, usually because a wheel is slipping on wet, icy, or gravelly road. That's normal. If the light is staying on solid, get it looked at when you can. It's not an emergency, but it means the system has turned itself off and isn't there to help you if a wheel loses grip.

The car has a sensor at each wheel that measures how fast that wheel is spinning. Stability control uses that information, along with a steering angle sensor and sometimes a yaw sensor that tells it whether the car is turning the way the steering wheel says it should. When the system sees a wheel slipping, or the car sliding differently than the steering suggests, it flashes the light and briefly applies brake pressure to individual wheels or cuts engine power to bring things back in line. A solid light means the computer has found a fault somewhere in that chain and shut the system off rather than let it act on bad information.

Commonest causes, roughly in order:

• A wheel speed sensor that's failed, dirty, or has a damaged wire. This is the most common one by far.
• Low tire pressure, or a tire that's a different size or wear level than the others, which throws off the wheel speed readings.
• A steering angle sensor that needs recalibrating, sometimes after an alignment or steering work.
• A bad connection or corroded wiring at one of the sensors.
• Less often, a problem with the ABS module itself.

Sometimes the ABS light comes on with it, since the two systems share the same wheel speed sensors. If your ABS light is on too, that's worth mentioning when you call.

Putting it right starts with pulling the fault codes, which points to which wheel and which part of the system is having trouble. A wheel speed sensor is usually a straightforward replacement. A wiring issue takes a bit more digging to find where the break or corrosion is. If tire pressure or mismatched tires turn out to be the cause, that's the cheapest fix there is. A steering angle sensor recalibration is a quick job with the right equipment. We can't say which of these it is without hooking up a scan tool and having a look, and we won't guess a price over the phone before that. If you want to bring it by, we're open Monday through Friday, 8 to 5.

Warning-light symbols and meanings vary by vehicle — always check your owner’s manual. This is general guidance based on what the light indicates, not a physical inspection, and a light on its own never names a failed part.