The B6 Passat has one brake pad warning sensor built into and fitted to the LEFT FRONT brake caliper.

This means that you will never get a warning light for the rear brake pads.

If the front right brake pad wears out before the front left one, you won’t know.

Not that good a warning system really.

This is page is only here to help anyone who wants to check the wiring because they think they have a fault.

The circuit is very simple and is not part of the onboard diagnostic check system so it cannot be monitored/checked using VCDS or similar.

If you suspect a wiring fault, you have to look for it using a test light and a multimeter.

The circuit looks like this; (The wiring should be the colours shown)

As long as the circuit is complete from Pin 22 on the dash panel insert, to earth. The warning light will remain off.

The brake pad has a thin wire embedded in it. When this wears through, by rubbing on the brake disc, the circuit is broken.

When the circuit is broken, the dash panel insert puts the brake pad warning light “ON”.

This means that a bad earth connection, dirty connector or broken wire will also cause the brake pad warning light to come on.