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U033B Software Incompatibility With Hybrid/EV Battery Interface Control Module B

Check engine lightUsually off
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Module B is the second interface board, and on GM's eAssist mild hybrids it is also the last: bulletin PIT5513D lists exactly two, K112A and K112B, for 2016–2018 Silverado and Sierra and the 2018 LaCrosse, both under the same part number 24282084. Since one spare fits either slot, the part number alone does not tell which position a board serves. FCA's 2017–2018 Pacifica Hybrid shows a related split with maker-specific codes P1A29 and P1A2A for cell supervisory circuits A and B; bulletin 08-047-20 clears them by reflashing the battery pack control module. Neither maker documents U033B itself. U01A1 means B is silent, U04A2 that its data are invalid.

Likely causes

Board B replaced with a spare carrying another software level
Battery controller software older than the board it has to accept
Identical boards A and B swapped during pack repair

Symptoms

  • Hybrid system or battery warning, often with the check engine lamp on PHEVs
  • Electric assist or electric driving reduced
  • Fault follows work on the battery pack

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€60–600
Time0.3–2 h

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

Parts involved

hv battery interface module b

Related codes

U01A1U04A2U033AU033C

References: static.nhtsa.gov, static.nhtsa.gov.