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!

Body generic / SAE

B0425

Audio Amplifier Internal Failure

The audio amplifier reports an internal self-test failure. Sound output may be distorted, missing on some channels, or the amplifier enters a protection mode.

SystemBody
Typegeneric / SAE
GroupB0
Range / number4 / 25

Possible causes

  • Amplifier internal fault high
  • Power supply or ground fault medium

Symptoms

  • Warning light or symbol related to the affected system
  • Comfort or safety function impaired

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 200–1500 €
  • Estimated time: 0.5–2.5 h
  • Component: audio amplifier
  • Component: infotainment 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