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

C0090

Hydraulic Brake Pressure Sensor Circuit

The brake pressure sensor in the master cylinder or hydraulic block reports an implausible signal or no signal. The fault disables ABS, stability control and brake assist.

SystemChassis
Typegeneric / SAE
GroupC0
Range / number– / 90

Possible causes

  • Pressure sensor element failed high
  • Sensor wiring fault medium

Symptoms

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

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 200–900 €
  • Estimated time: 1–3.5 h
  • Component: brake pressure sensor
  • Component: abs control module
  • Component: sensor wiring

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