C05C2: Brake Booster Motor A Over Temperature
Brake booster motor A exceeded its safe operating temperature. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
What C05C2 means
C05C2 is a generic OBD-II chassis code in the ABS & brakes group.
- Check engine light
- Usually on
- Emissions-related
- No
- Limp mode possible
- Yes
- Drive cycle to clear
- Required
Get it fixed
Post this code once and get quotes from local mechanics. Free to post.
Makes the repair and parts links below specific to your car. Kept in this browser only.
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Common causes
- 01Thermal overload from extended brakingMost likely
Can I drive with C05C2?
No. Stop and let the engine cool.
If the temperature gauge is high or you see steam, pull over and switch off. Driving an overheating engine can warp the head and blow the head gasket.
Why we rate it urgent
- Engine over-temperature can cause head-gasket and engine damage
- Can put the vehicle in limp mode (reduced power)
- Turns on the check engine light
- Needs a drive cycle to confirm a repair
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose C05C2
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just C05C2. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Fix other faults first
If other codes are stored, start with power-supply, sensor-circuit and communication codes. They can cause this code as a side effect.
- 3
Check live data
Watch the related sensor and actuator readings in live data (Brake booster motor A) and compare them with expected values in the service information for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Thermal overload from extended braking. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and complete a full drive cycle (cold start, idle, steady highway cruise, deceleration). The code is fixed when the related readiness monitor completes without it returning.
C05C2 repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Moderate
- Good DIY job?
- Usually a shop job
Needs a scan tool and some experience with testing.
Parts and systems involved
- Brake booster motor A
C05C2 FAQ
What does C05C2 mean?
C05C2 means “Brake Booster Motor A Over Temperature”. Brake booster motor A exceeded its safe operating temperature. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
Is C05C2 serious? Can I keep driving?
We rate C05C2 as urgent severity. No. Stop and let the engine cool. If the temperature gauge is high or you see steam, pull over and switch off. Driving an overheating engine can warp the head and blow the head gasket.
What causes C05C2?
The most common causes, from most to least likely: Thermal overload from extended braking. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix C05C2?
Typical labor is about $125–$625 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix C05C2 myself?
DIY difficulty is moderate. Most owners leave this to a shop because it needs involved testing or specialist tools. Always confirm the cause before buying parts.
Will C05C2 clear itself?
Once the fault is fixed, the check engine light usually goes off by itself after the system passes its self-test over several drive cycles. Clearing the code with a scan tool resets readiness monitors, so an inspection station may turn you away until a full drive cycle is completed.