EN

Severity: Moderate Code type: Generic (all makes) ✱

C0131 Code: ABS/TCS System Pressure Circuit (Brake Pressure Sensor)

The GM brake module sees an implausible or out-of-range signal from the brake pressure sensor.

Unverified: this manufacturer-specific definition comes from a single source or varies by model. Confirm it with a brand-specific scan tool.

Safety first · Consult a professional

  • Braking system affected: ABS may be disabled. Drive carefully and have it checked promptly.

At a glance

Severity: 3/5 – Moderate3/5

Severity: Moderate

Meaning
ABS/TCS System Pressure Circuit (Brake Pressure Sensor)
System
Brakes, ABS & Chassis · Chassis
Safe to drive?
With caution
Typical repair cost
$60–$2,000
DIY difficulty
Hard

On GM vehicles, C0131 means the EBCM has found a fault in the ABS/TCS system pressure circuit, which in practice is the brake fluid pressure sensor. That sensor reports how hard the driver is braking, and StabiliTrak, traction control and brake assist rely on it to build pressure on their own. It's a three-wire sensor with a 5 V reference, ground and a signal that rests near 0.5 V and rises with pedal force; if the signal is stuck, out of range or doesn't match what the pedal and deceleration suggest, the code sets. On many models the sensor is built into the modulator or master cylinder. The code number is manufacturer-defined, so check the description on other makes.

Can I keep driving? Normal braking and ABS are often still available, but stability control and traction control are switched off. Drive carefully in the wet or snow and get the sensor circuit diagnosed soon.

How to read C0131

How to read C0131C10213314
  1. C Chassis
  2. 0 Generic (SAE)
  3. 1 Brakes, ABS & Chassis
  4. 31 Specific fault

Symptoms

  • 'Service StabiliTrak' or 'Service Traction Control' message
  • ABS light on, sometimes only after a firm stop
  • Hill-start assist or brake assist inoperative
  • Warning that comes and goes over bumps or after rain
  • Other modules report lost communication or invalid data from the brake module

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Failed brake pressure sensor, often integral to the modulator or master cylinder 32%
  2. Fretting corrosion or loose terminals in the EBCM or sensor connector 20%
  3. EBCM internal fault in the sensor input or 5 V supply 16%
  4. Shared 5 V reference pulled down by another shorted sensor, or chafed wiring 14%
  5. Sensor not calibrated after brake work, module replacement or battery disconnection 10%
  6. Low system voltage during start-up 8%

Diagnosis step by step

Diagnostic flow: C01311Watch the brake pressure reading2Check reference and ground3Measure the signal voltage4Inspect the connectors for fretting5Run the calibration or learnprocedure6Decide on the repair

  1. Watch the brake pressure reading

    In the EBCM live data, the pressure value should read at or near zero with your foot off and rise smoothly as you press the pedal, often to well over 1,000 psi on a hard press. A frozen value, spikes or a reading with no pedal applied confirms the circuit fault.

    Tools: OBD-II scanner

  2. Check reference and ground

    Back-probe the sensor connector with the key on. You should see about 5 V on the reference and less than 0.1 V on the ground; a low reference means something on that shared 5 V circuit is shorted.

    Tools: Multimeter

  3. Measure the signal voltage

    With no pedal applied, the signal typically rests around 0.5 V and climbs toward 4.5 V as pressure rises. Compare the reading at the sensor with the reading at the EBCM; any difference points to the wire or connector in between.

    Tools: Multimeter

  4. Inspect the connectors for fretting

    Unplug the EBCM and sensor connectors and look for dull, dark wear marks on the terminals. Tighten spread terminals or repair them, and apply dielectric grease only if the service information allows it.

    Tools: Screwdriver, Flashlight

  5. Run the calibration or learn procedure

    Many GM vehicles need a brake pressure sensor calibration or pedal-position learn after battery disconnection, brake work or module replacement. Run it with the engine off and your foot off the pedal, then recheck the live data.

    Tools: OBD-II scanner

  6. Decide on the repair

    If reference, ground and wiring are good and the signal is still wrong, replace the sensor, or the modulator or master cylinder if it's integral. Bleed the brakes with the scan tool where required and road test.

    Tools: OBD-II scanner

Where the parts are

Ignition: coils and spark plugs per cylinder – C01311234567
Ignition: coils and spark plugs per cylinder
  1. 1Ignition coil
  2. 2Spark plug
  3. 3Fuel injector
  4. 4Camshaft sensor
  5. 5Crankshaft sensor
  6. 6Engine computer (ECM)
  7. 7Intake manifold

Repair options & costs

RepairDIY?Estimated cost
Repair connector terminals or wiring No $80–$250
Brake pressure sensor calibration with scan tool No $60–$150
Replace separate brake pressure sensor No $150–$400
Replace master cylinder with integral sensor No $350–$800
Replace modulator (BPMV) with integral sensor, bleed No $800–$2,000

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Notes by brand

Chevrolet

On many GMT900-generation Silverado, Tahoe and Suburban trucks the brake pressure sensor is part of the modulator valve assembly, so a confirmed sensor fault usually means replacing that assembly rather than a separate sensor.

Field data

Chevrolet 7 Malibu Hybrid, Captiva, Malibu

Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.

Emissions / smog test impact

Depends

C0131 isn't read during an OBD emissions test. States with a safety inspection may reject a vehicle with the ABS or stability warning lit.

Frequently asked questions

What is the brake pressure sensor for?

It tells the brake module how hard you're braking. Stability control and brake assist need that number to decide how much pressure to add on their own, so without it they shut off.

Why did C0131 appear after I replaced the battery?

Some GM models lose the sensor's zero-point calibration when power is interrupted. Running the calibration with a scan tool often clears the fault without any parts.

Is C0131 related to the brake light switch code C0161?

They're often checked against each other. The module compares the brake switch with the pressure reading, so a faulty switch can make the pressure signal look wrong and the other way round.

Can I just replace the sensor?

Only if it's a separate part on your vehicle. On many GM models it's built into the modulator or master cylinder, which makes the repair more expensive and requires bleeding.

Sources