C0266Active Brake Booster
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- Active brake booster faults are filed under C0266 by no maker, and the reachable J2012 lists omit the code. The number is a GM one: it shows up among PIP5094's keywords, and AA1Car words it exactly like C0265, EBCM Relay Circuit, so on GM vehicles it points to the relay that powers the ABS valves and pump rather than to a booster. The part in the title is a booster that builds pressure without the driver, either a vacuum unit with a solenoid or an electromechanical design such as Bosch's iBooster, whose motor works independently of engine vacuum and can brake on its own for assistance functions. On a vehicle with such a booster, its own maker-specific codes cover faults; with C0266, first find out which module stored it.
- What you may notice
- ABS or brake warning lamp on
- Assistance functions such as automatic braking unavailable
- Likely causes
- PossibleOn GM vehicles fault in the brake module relay supply (fuse, contact, ground)
- RareFaulty actuator or motor of an active booster
- RareDamaged wiring or connector to the booster or relay
- Repair
- Hard · Usually a job for a workshop.Typical cost: €30 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.