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

P2CB7

Turbocharger/Supercharger Boost Pressure B Not Detected – Mechanical

The boost pressure on branch B is not detected during operation. Mechanical fault — turbo seized, charge pipe disconnected, or wastegate fully open.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / numberC / B7

Possible causes

  • Turbocharger B seized high
  • Charge pipe disconnected medium

Symptoms

  • Check engine light on
  • Significant power loss / limp mode
  • Possible blue or black smoke from exhaust
  • Whistling or hissing sound from intake

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 400–4000 €
  • Estimated time: 2–12 h
  • Component: turbocharger b
  • Component: wastegate b
  • Component: boost pressure sensor b
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required
  • limp mode possible

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