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!

Powertrain generic / SAE

P2526

Vacuum Reservoir Pressure Sensor Circuit Range/Performance

The vacuum reservoir pressure sensor is electrically intact, but the reading does not match the model — vacuum that does not build up after pump activation, does not bleed off when consumers draw, or stays at one value. Often a partly clogged hose, a leaking reservoir or an aged sensor.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 26

Possible causes

  • Leaking reservoir or vacuum line high
  • Aged sensor with offset drift medium
  • Sensor element aged beyond calibration window low

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 120–600 €
  • Estimated time: 0.5–2.5 h
  • Component: vacuum reservoir
  • Component: vacuum lines
  • Component: vacuum pump
  • MIL / check engine light

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