Chassis, generic

C0571 Brake Pressure Sensor C Circuit Low

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

Brake pressure sensor C is an additional hydraulic pressure sensor whose job depends on the brake system; each maker assigns the letter itself. GM uses C0571 in three variants. In the 2016–2019 hybrid brake control modules it is master cylinder pressure sensor 1, set when the signal line shows no voltage difference to ground for 0.1 s. In a 2019 EBCM with integrated booster it is the secondary circuit pressure sensor, set below 4.61 % of its supply within 100 ms. In the 2023 and 2025 tables a SENT master cylinder sensor pinned at its minimum of −1480 kPa for 0.96 s sets it. GM rates every variant Type A, MIL after one trip. ABS, stability control and regenerative blending are then restricted.

Likely causes

Sensor signal line shorted to ground in the harness or connector
Sensor supply missing, so the output stays at its lowest value
Defective pressure sensor, often integrated in the hydraulic or brake module

Symptoms

  • Check engine light together with ABS or stability warning (GM)
  • Regenerative braking or brake assist reduced, pedal feel changed
  • Brake pressure reading on the scan tool stuck at its minimum

Repair estimate

DifficultyHardWorkshop job
Parts and labour€60–2,500
Time0.5–4 h

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

Parts involved

brake pressure sensor csensor wiringbrake control module

Related codes

C0572C0573C0574C059CC053E

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, techtips.ie.