Seeing your ABS light and traction control (TCS/ESC) light glow at the same time is alarming, but the pairing is actually a helpful clue. These two systems are closely linked, and when both light up together the cause is almost always shared. Here is what is going on.
Why they come on together
Traction control and stability control are built on top of the ABS system - they use the very same wheel-speed sensors and the same hydraulic control unit that ABS uses. So when the ABS module loses a signal it needs, it disables ABS AND the traction/stability features that depend on it, lighting both warnings at once. The tie is by design. For background, see how ABS works.
The most common cause: a wheel-speed sensor
By far the most frequent trigger is a single failed or dirty wheel-speed sensor, or a damaged sensor wire or reluctor ring. If one wheel stops reporting its speed, the module cannot compare all four wheels, so it shuts off ABS and traction together. A scan tool will pull a code pointing to the specific corner. Metal debris or a corroded sensor tip is a common, cheap fix.
Other causes to check
Beyond a wheel sensor, both lights can share a cause in low or contaminated brake fluid affecting the ABS pump, a blown fuse, a low battery or bad alternator (voltage dips confuse the module), or a fault in the ABS control unit itself. Start with the simple stuff: check the fluid level and condition - see brake fluid color meaning - and battery health before assuming the worst.
Is it safe to drive?
Your normal brakes still work - only the anti-lock and traction assists are offline, so the car stops as a pre-ABS vehicle would. Drive gently, avoid hard braking on slick roads, and get it scanned soon. If your regular ABS warning light alone is on, the same diagnostic path applies. Do not ignore it - you have lost a safety net.