C0022 code meaning
Brake Booster Solenoid
What C0022 means
C0022 covers the solenoid valve of an electronically controllable brake booster. Patent literature shows a vacuum booster that works in two ways: by the driver's pedal in normal braking, and through a solenoid valve that changes the pressure in an auxiliary chamber so the booster applies the brakes without the pedal. NHTSA's brake study describes the conventional vacuum booster, which this valve extends, sitting ahead of the master cylinder. The module checks the coil circuit for opens, shorts and resistance out of range and whether assist follows the command. A fault removes automatic braking and can change pedal effort; the brake or ABS lamp lights. No manufacturer documents this code publicly with a retrievable bulletin.
C0022 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0022
- Changed brake pedal effort or feel
- Noise from the brake system
- ABS or brake warning lamp on
Common causes of C0022
- Most likelySolenoid coil open or shorted
- PossibleCorroded connector or chafed wiring
- Less likelyInternal booster assembly fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake booster solenoid
What each part of C0022 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 22 | The exact fault in that area. |
What to do next
- Note C0022 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C0022
What does C0022 mean?
C0022 means "Brake Booster Solenoid". C0022 covers the solenoid valve of an electronically controllable brake booster. It is a generic code, so it means the same on every make.
Is it safe to drive with C0022?
Drive gently and only to a workshop. With C0022 the car can go into limp mode (reduced power) to protect itself.
Will C0022 fail an emissions test?
C0022 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C0022 to fix?
Difficulty: workshop only. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will C0022 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.