Powertrain, generic (extended)

P25C6 Brake Booster Temperature Sensor A Circuit Low

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

P25C6 means the signal of brake booster temperature sensor A is too low, which GM describes as the sensor line being shorted to ground. GM uses the code on the 2023 Corvette Z06 (table 23OBDG07, EBCM section) and keeps the same logic in its 2024 and 2025 tables 24OBDG07 and 25OBDG03A: the check runs continuously with the ignition on, needs the condition five times in a row within 0.6 s and is rated Type B, so the MIL comes on after two trips. The voltage limit for the low side is left blank in the published tables. A low reading can also come from a pinched harness at the booster, from water in the connector or from a sensor that has failed internally. The sibling P25C7 covers a short to supply, C0579 the same fault on the second sensor.

Likely causes

Sensor signal wire shorted to ground
Moisture in the booster connector
Internal short in the temperature sensor

Symptoms

  • Check engine lamp after two trips
  • Brake system warning message
  • Brake assistance may be limited

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–2,500
Time1–4 h

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

Parts involved

electric brake boostertemperature sensorwiring harness

Related codes

P25C7P25C4C0579C05B3

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