C0046 code meaning
Brake Pressure Sensor A/B
What C0046 means
A correlation code for the pair of brake pressure sensors A and B, set when their readings do not agree within the expected tolerance. Where C0044 and C0045 flag a single-sensor electrical fault, this code is a plausibility fault: at the same instant both sensors should report consistent pressure (allowing for their known relationship), and a persistent mismatch indicates one sensor has drifted, a hydraulic fault separates the circuits, or a signal is corrupted. The stability and brake modules rely on agreement to trust the pressure reading for stability, brake assist and brake-by-wire control. A fault disables those functions and sets the ABS or brake warning lamp while base braking remains. NHTSA lists C0046 in the J2012 table of its EPS report. No manufacturer documents it publicly.
C0046 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0046
- ABS or brake warning lamp on
- Stability and assist functions disabled
- Changed brake assist behaviour
Common causes of C0046
- Most likelyOne pressure sensor drifted or biased
- PossibleHydraulic fault separating the circuits
- Less likelySignal corruption or wiring fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake pressure sensors
What each part of C0046 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 46 | The exact fault in that area. |
What to do next
- Note C0046 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 C0046
What does C0046 mean?
C0046 means "Brake Pressure Sensor A/B". A correlation code for the pair of brake pressure sensors A and B, set when their readings do not agree within the expected tolerance. It is a generic code, so it means the same on every make.
Is it safe to drive with C0046?
Drive gently and only to a workshop. With C0046 the car can go into limp mode (reduced power) to protect itself.
Will C0046 fail an emissions test?
C0046 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 C0046 to fix?
Difficulty: workshop only. A typical repair takes 1.5 to 4 hours of work. This is a job for a workshop.
Will C0046 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.