Network, generic

U01AF Lost Communication With Hybrid/EV Battery Interface Control Module P

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

U01AF closes the row and stands for battery interface control module P, the sixteenth monitoring board; no manufacturer documents it publicly. Some packs exceed that count: according to Wikipedia the Hummer EV battery consists of 24 Ultium modules, although that platform monitors wirelessly and GM does not publish how it maps modules to codes. The code is easily mixed up with its neighbours. U0111, U0112, U014A and U014C mean that a battery energy control module itself has vanished from the vehicle network, and U019B points to the on-board charger. U01AF, by contrast, describes a sub-board inside the pack that only the battery controller can see, so that controller must itself be awake and reachable to log it.

Likely causes

Internal link to module P interrupted
Battery interface control module P defective

Symptoms

  • Battery warning while the battery controller itself still communicates
  • Power limited, charging blocked

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 pcommunication bus

Related codes

U01AEU04B0U0349U0111U019B

References: en.wikipedia.org, law.cornell.edu, en.wikipedia.org.