C05C4 code meaning
Brake Pressure Sensor F Missing Calibration
What C05C4 means
The brake controller finds no stored calibration (offset or zero point) for pressure sensor F, the sixth hydraulic pressure sensor in its numbering. Which physical sensor carries the letter F is up to the maker, and none publishes C05C4. Comparable codes exist for sensors A and B: GM checks sensor B in its hybrid brake controller via test pulses after offset compensation, and Saab/GM calls for a scan-tool pressure sensor calibration after replacing the EBCM or the modulator. Hitachi learns pressure sensor zeros only while the master cylinder is pressureless and the pedal is released. A new module or hydraulic unit without the follow-up calibration is the usual cause. C05C5 to C05C8 cover the sensor's signal faults.
C05C4 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.3 to 1 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C05C4
- ABS, ESC or brake warning lamp on
- Stability control or brake assist functions disabled
Common causes of C05C4
- Most likelyCalibration skipped after module or hydraulic unit replacement
- PossibleCalibration interrupted by brake application or low voltage
- Less likelyCalibration data lost in the module memory
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake pressure sensor fBrake control module
What each part of C05C4 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| C4 | The exact fault in that area. |
What to do next
- Note C05C4 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 C05C4
What does C05C4 mean?
C05C4 means "Brake Pressure Sensor F Missing Calibration". The brake controller finds no stored calibration (offset or zero point) for pressure sensor F, the sixth hydraulic pressure sensor in its numbering. It is a generic code, so it means the same on every make.
Is it safe to drive with C05C4?
Drive gently and only to a workshop. With C05C4 the car can go into limp mode (reduced power) to protect itself.
Will C05C4 fail an emissions test?
C05C4 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 C05C4 to fix?
Difficulty: medium. A typical repair takes 0.3 to 1 hours of work. This is a job for a workshop.
Will C05C4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.