Chassis, generic

C063C Brake Pressure Sensor H Range/Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

Sensor H gives an electrically valid yet implausible pressure. In Toyota's eight-sensor patent the check connects a pressure source to a brake cylinder: both readings should then nearly match, and a gap beyond a threshold means one of the two sensors, the passage or the cylinder is at fault; the switch-over is preferably made at standstill. Ford's hybrid brake, which has only two pressure sensors, shows typical limits: a P1 offset outside ±16 bar, or both sensors more than 50 bar apart for 100 ms. That Ford needs no letters beyond A and B also shows that H exists only in larger systems. No maker documents C063C. FMVSS 126 requires a telltale for ESC malfunctions, so the driver gets a warning lamp that goes out only after the fault has gone.

Likely causes

Offset or gain of sensor H drifted out of tolerance
Restricted passage or faulty brake cylinder so pressures really differ
Air in the brake fluid distorting the pressure build-up

Symptoms

  • ESC malfunction telltale and ABS lamp on
  • Changed pedal feel or reduced brake assistance

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–1,800
Time0.5–4 h

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

Parts involved

brake pressure sensor h

Related codes

C0639C063AC063BC0638C0640

References: patents.google.com, fordservicecontent.com, law.cornell.edu.