Network, generic

U0296 Lost Communication With AC/DC Converter Control Module A

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

An AC/DC converter rectifies alternating current; in plug-in vehicles the best known example is the on-board charger, which also runs in the opposite direction of an inverter feeding a motor. U0296 means converter module A no longer reports on the bus. CARB obliges plug-in hybrids to detect charger malfunctions that prevent full charging or limit the charge rate. Volvo is the maker that names the code: on plug-in XC60 and XC90 models from 2022, brake control module 2 logs BCM2-U029600, the ESC lamp comes on and Pure mode is locked out whenever a third-party device or Y-splitter loads the diagnostic socket (TJ 36559). On 2016–2018 T8 models the code appeared intermittently next to rear-axle inverter faults and cleared with inverter software (TJ 33723).

Likely causes

Aftermarket device or Y-splitter on the diagnostic connector disturbing the bus
Outdated software in the converter or inverter module
Supply, ground or bus wiring of converter A faulty
Converter module A internally failed

Symptoms

  • ESC or hybrid system warning in the cluster
  • Pure electric driving not available
  • Charging from the grid not possible

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–3,000
Time0.3–5 h

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

Parts involved

ac dc converter module avehicle bus wiring

Related codes

U0297U0597U0598U019B

References: static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu.