C004A Brake Lining Wear Sensor

Covers the brake lining (pad) wear sensor circuit, which warns the driver when friction material is worn to its limit. Electronic wear sensors use a loop embedded in the pad that the disc contacts and opens, or a wear-indicator circuit, as the lining wears down; the module reports pad wear and may store this code for an open, shorted or implausible sensor circuit as well as for a genuine worn-pad signal. It is an advisory function rather than a safety-critical control loss: braking and ABS continue, but the driver is told to inspect or replace the pads. The code can appear after pad replacement if the sensor was not renewed or reconnected. Delphi describes both the single loop and two-stage sensors with two resistor circuits. No manufacturer documents this code publicly.

Likely causes

Symptoms

• Brake pad wear warning message
• Warning lamp on
• Possible squeal from a mechanical indicator

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: delphiautoparts.com, rosap.ntl.bts.gov, en.wikipedia.org.