Chassis, generic

C05A0 Brake Pressure Sensor E Circuit High

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

C05A0 is set when sensor E reports a voltage above its usable range. In the Denso patent on vehicle pressure sensors the band from 4.7 to 5 V is reserved for faults, and a lost ground wire pushes the output into it through the divider formed by the sensor's internal resistance and the module's pull-down resistor. Honeywell's ratiometric transducers deliberately drive their output to 97.5 % of supply on an internal fault or overpressure, so a high code can also come from the sensor itself. A short to the 5 V reference or to battery voltage is the other common case. No maker publishes C05A0; GM's 2019 EBCM uses more than 95.24 % of supply for 100 ms on comparable sensors, Type A. The module would otherwise see braking that is not happening, so it ignores the sensor and limits ESC.

Likely causes

Signal shorted to the 5 V reference or to battery voltage
Open sensor ground lifting the output to the upper rail
Sensor signalling an internal fault at full scale

Symptoms

  • ABS/ESC warning lamp on
  • Stability control unavailable, brake lights may be requested falsely on some systems

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 esensor wiring

Related codes

C059FC05A1C05A2C059EC05C7C0576

References: patents.google.com, prod-edam.honeywell.com, gsi.ext.gm.com.