Chassis, generic

C0045 Brake Pressure Sensor B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

C0045 covers brake pressure sensor B, the second pressure transducer in the ABS/ESC hydraulic unit next to sensor A (C0044). Two sensors let the module watch both brake circuits or check one reading against the other for stability control, brake assist and brake-by-wire functions. The code sets for a signal out of range, an open or short, or a value that disagrees with sensor A or the pedal demand. Where the sensor sits inside an integrated brake unit, repair usually means replacing the whole unit. NHTSA's EPS safety report lists C0045 with this J2012 meaning. Older GM vehicles use C0045 for the left rear wheel speed sensor circuit instead (GM PIE0456, 16-NA-248), so the make decides what a stored C0045 means.

Likely causes

Pressure sensor failed or out of range
Fault internal to the integrated brake unit
Signal does not correlate with sensor A

Symptoms

  • ABS or brake warning lamp on
  • Stability and assist functions disabled
  • Changed brake assist behaviour

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€400–2,200
Time1.5–4 h

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

Parts involved

brake pressure sensor b

Related codes

C0044C0046C0024

References: rosap.ntl.bts.gov, static.nhtsa.gov, static.nhtsa.gov, rosap.ntl.bts.gov.