Chassis, generic

C0023 Stop Lamp Control

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

Covers the stop lamp (brake light) control circuit as driven or monitored by the brake or stability control module. Modern ABS/ESC systems can command the stop lamps during autonomous braking events such as traction control, stability control and automatic emergency braking, independent of the driver pressing the pedal, and they monitor the circuit for opens, shorts and lamp-output disagreement. The code is stored when the commanded stop lamp state does not match the measured output or the circuit is faulty. Effects range from stop lamps that stay on or off to disabled driver-assist functions that rely on brake-light actuation. Mazda stores C0023:14 as a brake light circuit malfunction and names a retrofitted brake light flasher as one trigger (service alert SA-041-26). NHTSA's brake study lists brake lights on/off as a CHB output.

Likely causes

Open or shorted stop lamp wiring
Failed lamp or output driver
Faulty brake switch signal

Symptoms

  • Stop lamps stay on or do not light
  • Stability or driver-assist functions disabled
  • ABS or stability warning lamp on

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–400
Time0.5–2 h

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

Parts involved

stop lamp control circuit

Related codes

C0040C0041C0042

References: static.nhtsa.gov, rosap.ntl.bts.gov, en.wikipedia.org.