C0131 code meaning
Master Cylinder Pressure Sensor Range/Performance
What C0131 means
C0131 is not in the accessible J2012 lists; GM and Saab use it for the brake pressure sensor that measures master cylinder pressure inside the modulator. In the Saab 9-5 up to 2010 a signal above 4.75 V or under 0.25 V lasting 0.1 s, or a supply outside 4.4–5.6 V, sets it and ABS, TCS and ESP go out of service. The later 9-5 and the 9-4X call it Traction Control System Pressure Circuit, check the sensor against the pedal message from the body module and against vehicle deceleration, and switch off traction and stability control. GM bulletins PIC5704C to H (Sonic, Spark, Trax, Encore 2012–2022) report C0131 after a modulator swap when shipping material was left on the sensor, which then reads 5 V all the time.
C0131 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 C0131
- Traction/stability control warning on, systems switched off
- On some models ABS lamp on as well
Common causes of C0131
- Most likelyBrake pressure sensor in the modulator faulty or out of calibration
- PossibleShipping material left on the sensor after modulator replacement (GM)
- PossibleFault on the 5 V reference or signal circuit of the sensor
- Less likelyIncorrect brake pedal signal used for the plausibility check
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Master cylinder pressure sensorABS control moduleEsp control module
What each part of C0131 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 31 | The exact fault in that area. |
What to do next
- Note C0131 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 C0131
What does C0131 mean?
C0131 means "Master Cylinder Pressure Sensor Range/Performance". C0131 is not in the accessible J2012 lists; GM and Saab use it for the brake pressure sensor that measures master cylinder pressure inside the modulator. It is a generic code, so it means the same on every make.
Is it safe to drive with C0131?
Drive gently and only to a workshop. With C0131 the car can go into limp mode (reduced power) to protect itself.
Will C0131 fail an emissions test?
C0131 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 C0131 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will C0131 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.