Chassis, generic

C0131 Master Cylinder Pressure Sensor Range/Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Brake pressure sensor in the modulator faulty or out of calibration
Shipping material left on the sensor after modulator replacement (GM)
Fault on the 5 V reference or signal circuit of the sensor
Incorrect brake pedal signal used for the plausibility check

Symptoms

  • Traction/stability control warning on, systems switched off
  • On some models ABS lamp on as well

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–900
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

master cylinder pressure sensorabs control moduleesp control module

Related codes

C0044C053DC0540C0161

References: saabwisonline.com, saabwisonline.com, saabwisonline.com, static.nhtsa.gov.