Chassis, generic

C0043 Brake Pedal Position Sensor Circuit B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

Covers circuit B of the brake pedal position sensor, the redundant second channel that the module cross-checks against channel A (C0042). Dual-channel pedal position sensors provide two independent voltage signals, often with opposite slopes, so the module can detect a single-channel fault by correlation. This code is set when channel B is out of range, open, shorted or does not track channel A within tolerance. It supports brake-by-wire assist, regenerative braking blending and precise stop-lamp and cruise control. A fault can disable assist and cruise functions and set a warning lamp while base braking remains. No manufacturer documents this code publicly; NHTSA's EPS report lists C0043 in its J2012 table, and its brake study explains how the module uses the pedal sensor to read driver intent.

Likely causes

Pedal position sensor channel B out of range
Channel A/B signals do not correlate
Harness or connector fault

Symptoms

  • Brake lights stay on or behave oddly
  • Cruise control will not set
  • ABS or brake warning lamp on

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–350
Time0.4–1.5 h

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

Parts involved

brake pedal position sensor

Related codes

C0042C0040C0041

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