Body, generic

B0425 Audio Amplifier Internal Failure

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Every accessible J2012 list lacks B0425, and no maker's literature mentions it, leaving the code itself unverified. The title concerns a fault inside the separate audio amplifier rather than in its wiring. Amplifier chips such as TI's TAS6424E-Q1 check each channel for open load, shorted load and shorts to battery or ground, and raise a warning on clipping or overtemperature. In GM's Global A electronics, as fitted to 2011 Saab 9-5 and 9-4X cars, the amplifier stores no codes of its own; the radio watches the PWM mute line and logs B1287 if that line is open or shorted 0.4 s after it switches the amplifier on. Typical signs are silence or crackling on all amplified channels. Communication loss with the amplifier is U0186, a fault of the head unit B0420.

Likely causes

Output stage or internal electronics of the amplifier failed
Amplifier overheated, e.g. under a seat or in the boot without airflow
Moisture or water in the amplifier housing or plug
Shorted speaker or wiring that has overloaded the output stage

Symptoms

  • No sound or only very low volume from the amplified speakers
  • Crackling, hum or distortion, often worse when warm
  • Subwoofer or premium sound channels drop out

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–1,500
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

audio amplifierinfotainment module

Related codes

B0420U0186U0262

References: ti.com, ti.com, saabwisonline.com, saabwisonline.com.