C05A1Brake Pressure Sensor E Circuit/Open
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- This code points to an interrupted circuit of sensor E: a broken signal, 5 V supply or ground wire, or a connector that has lost contact. No maker documents C05A1 publicly. Whether an open is recognised as such or as low or high depends on the input circuit, which is why many systems book it under C059F or C05A0 instead. Honeywell specifies that with an external pull-up resistor a power or ground loss drives the output high, with a pull-down low. A Denso patent adds a check for creeping contact resistance, which produces in-between voltages that such resistor schemes miss: the supply is briefly raised so the sensor outputs a fixed test voltage. Bosch's EBS monitors each of its pressure sensors separately. Check connector and wiring before condemning the sensor.
- What you may notice
- ABS/ESC warning lamp on, possibly coming and going
- Stability control and brake assist switched off
- Likely causes
- LikelyCorroded or loose connector at the sensor or hydraulic unit
- PossibleBroken signal, supply or ground wire
- RareInternal open circuit in the sensor
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.