C064A code meaning
Brake Pressure Sensor M Circuit High
What C064A means
C064A: the voltage from sensor M exceeds what any valid pressure would give. On WABCO's Trailer EBS D the brake pressure sensor of an extra EBS relay valve, for example on a drawbar trailer's front axle, draws its supply from the trailer modulator and returns its actual value as an analog signal; all active sensors share supply outputs that are protected against short circuits. A short from that supply to the signal pin therefore drives the reading to the top. Kelsey-Hayes adds the opposite path: an open circuit lets a bridge output rise to supply level, so a high code does not exclude a broken wire. No passenger-car maker documents C064A. With the channel discarded, the system falls back to reduced functions.
C064A at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C064A
- Brake or ABS warning lamp on
- Load-dependent or electronic pressure control disabled
Common causes of C064A
- Most likelySignal pin shorted to the sensor supply or battery voltage
- PossibleOpen sensor ground or signal line letting the input float high
- Less likelySensor output stuck at its upper limit
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake pressure sensor mSensor wiring
What each part of C064A means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4A | The exact fault in that area. |
What to do next
- Note C064A 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 C064A
What does C064A mean?
C064A means "Brake Pressure Sensor M Circuit High". C064A: the voltage from sensor M exceeds what any valid pressure would give. It is a generic code, so it means the same on every make.
Is it safe to drive with C064A?
Drive gently and only to a workshop. With C064A the car can go into limp mode (reduced power) to protect itself.
Will C064A fail an emissions test?
C064A 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 C064A to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will C064A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.