OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Chassis generic / SAE

C0277

Brake Booster Vacuum Sensor Circuit Malfunction

The brake control module has detected an implausible signal from the booster vacuum sensor. Loss of vacuum signal can cause hard pedal and reduced power assist.

SystemChassis
Typegeneric / SAE
GroupC0
Range / number2 / 77

Possible causes

  • Vacuum sensor failed high
  • Vacuum leak in booster or hose medium

Symptoms

  • ABS warning light on
  • ESC/stability control deactivated
  • Possible reduced brake assist
  • Speedometer may behave erratically

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 80–500 €
  • Estimated time: 0.5–2 h
  • Component: brake booster
  • Component: vacuum sensor
  • Component: brake control module

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication