Network, generic

U04AF Invalid Data Received From Hybrid/EV Battery Interface Control Module O

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

U04AF concerns interface module O, the fifteenth board. In practice a data fault of this kind often follows work on the pack: if a replaced board and the battery controller interpret messages differently, frames arrive formally intact but fail range or counter checks. The software sibling U0348 and a search for available updates therefore belong next to this code, as does U01AE for a module that stopped sending. GM's 2015 note PIC6080 for the 2011–2014 Volt, ELR and Ampera says to reprogram the battery and hybrid controllers first when cell codes are spread over several pack sections, and to call technical assistance only when all of them sit on one interface board. No maker documents U04AF; the letter O only exists on very large packs.

Likely causes

Software levels of replaced board and battery controller do not match
Interface control module O faulty
Plug not fully seated after pack repair

Symptoms

  • Battery warning shortly after a battery repair
  • Reduced power or charging

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–3,500
Time1–10 h

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

Parts involved

hv battery interface module o

Related codes

U01AEU0348U04AEU04B0

References: static.nhtsa.gov, gsi.ext.gm.com.