C05ADBrake Blending System Performance
- Generic OBD-II code · Chassis
- Turns on the check-engine light
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- C05AD is the overall check of a blended brake: does the hydraulic pressure built by wire match what the controller asked for? GM's 2016 and 2019 hybrid tables (brake module BSC1) compare actual and target boost-piston pressure, for the by-wire side as well as the master cylinder side: more than 4,000 kPa too high points to a false high sensor value, more than 1,500 kPa too low to a low sensor value, an empty accumulator, a weak pump, air or a leak. It sets within 0.5–1 s, Type A with MIL. GM proves the repair by driving to about 25 mph and braking gently at around 3,000 kPa rear pressure twice. Bosch notes that blending generator and hydraulic braking is a core job of brake-by-wire, and Ford Otosan's patent compensates regeneration gaps with friction braking.
- What you may notice
- Brake warning and check engine lamps
- Soft or inconsistent pedal, braking stronger or weaker than expected
- Regenerative braking reduced
- Likely causes
- LikelyBrake pressure sensor reading too high or too low
- PossibleLow accumulator pressure or weak hydraulic pump
- PossibleAir in the hydraulic circuit after service
- RareExternal or internal leak in the brake hydraulics
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.