P0572–P0719 Brake Switch A Circuit Low

Which code is which

Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.

The definition

P0572: Brake Switch A Circuit Low.

P0572 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.

What to check first

Cheapest and fastest checks first:

1. Unplug the sensor. If the reading jumps to full scale, the wiring is fine and the sensor has failed low.
2. Check the sensor's 5V supply and its earth before condemning the sensor itself.

What actually causes this on a VAG

VAG brake light switches send two separate signals so the car can cross-check them - one confirms the brake lights, the other tells the engine, gearbox and cruise control that your foot is on the brake. This code means one of those signals is reading low, or the pair no longer agree. Typical symptoms are cruise control refusing to engage, brake lights stuck on or not working, an automatic that will not come out of Park, and sometimes reduced throttle response; on some cars the ESP or traction control light comes on too, because the stability system uses the same signal. Before anything else, have someone stand behind the car and confirm the brake lights actually work - that is the part of this fault that matters on the road.

Most likely causes, in order

1. Failed brake light switch. This is easily the most common cause on these cars and the switch is an inexpensive part that clips into the pedal bracket. It can usually be confirmed by watching the brake switch status in live data while an assistant presses and releases the pedal slowly - a faulty one will stick, flicker, or show the two channels disagreeing.
2. Switch not correctly set against the pedal. Many VAG brake light switches are self-adjusting: they set their own plunger depth as they are fitted, and will read wrongly if that is done out of sequence, or if the switch has been knocked or partly pushed out of its bracket. Check it is fully clipped in and sitting square, and follow the fitting procedure for your car, before condemning it.
3. Connector or wiring at the pedal box. The plug on the switch sits in the footwell where feet, mats and dropped items reach it. Look for a plug that is not fully latched, damaged pins, or wires pulled at the back of the connector. Free to check and worth doing before buying anything.
4. Worn pedal bracket or pushrod play. Wear in the pedal pivot or the linkage can leave the switch plunger not quite following the pedal. Rare compared with the switch itself, but worth a look if a new switch does not cure it.

Worth knowing: The switch is cheap, but fit a good-quality one and set it correctly. A poor part or a badly seated one can leave the brake lights permanently on - which flattens the battery and, more to the point, means the driver behind cannot tell when you are braking - or leave them not working at all, which is neither safe nor legal. Check the lights before you drive anywhere, and clear the stored fault after the repair, as cruise control will often stay disabled until you do.

Common questions

What does P0572 mean?

P0572 means Brake Switch A Circuit Low. The voltage on this circuit is sitting near zero. Typically a short to earth, or a sensor that has failed to its low end.

Can I drive with P0572?

This affects a system that helps you stop or stay straight. Assume ABS and stability control are reduced or switched off until it is fixed.

Related reading

• Several warning lights on at once: usually one cause, not many
• Humming or Whining Noise on a VW or Audi: How to Place It
• The 10-minute diagnostic check before you buy a used VW or Audi
• Why the same fault code has completely different causes