Network, generic

U0262 Lost Communication With Audio Amplifier B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Large sound systems may use a second external amplifier, audio amplifier B. Such amplifiers take part in network traffic: a patent on modular add-on sound systems explains that the factory amplifier decodes gain commands that the head unit sends over the CAN bus, and that a replacement amplifier must therefore understand the maker's bus format, such as GMLAN. No manufacturer documents U0262 publicly or says which speakers B drives. The single-amplifier case shows typical causes: on the 2023 Mazda CX-50, static or silence with U0186:08 (amplifier unreachable) and U2145:08 came from rear harness connectors 0920-114 and 0920-115D that were not locked (SA-058-22). For B, a receiver such as the head unit sets the code once its frames stop. The speakers fed by B fall silent; U0563 means corrupt data.

Likely causes

Amplifier connector not locked or pushed back, often in the rear harness
Amplifier B without power or ground (own fuse, switched supply)
Aftermarket audio installation that removed or bypassed the second amplifier
Internal failure of amplifier B

Symptoms

  • Some speakers silent while others still play
  • Static, crackling or sound dropping out

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–900
Time0.3–2 h

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

Parts involved

audio amplifier bvehicle bus wiring

Related codes

U0563U0186U0487U0184

References: patents.google.com, static.nhtsa.gov.