Code U0112 on the 2022 Volkswagen Jetta indicates lost communication with a secondary battery energy control module. VW vehicles with advanced start-stop systems, mild hybrid configurations, or multiple battery systems use additional battery management modules.
VW Battery Management Architecture
Volkswagen's energy management system may use multiple modules to manage primary and auxiliary batteries. The secondary module may monitor an auxiliary battery for start-stop functionality, manage power distribution, or handle specific electrical loads. Communication loss affects the coordinated energy management strategy.
Feature Impact
With U0112 active, start-stop functionality is typically disabled. The vehicle may show battery or electrical system warnings. Power-intensive features may be restricted to preserve main battery charge. The vehicle remains functional for basic driving, but energy efficiency features are compromised.
Diagnostic Process
VW places auxiliary batteries and their management modules in various locations - under the hood, in the trunk, or under seats. Identify your Jetta's configuration using service information. Check module connectors for VW's common green corrosion issue. Verify power, ground, and CAN communication at the secondary module.
Repair Path
Address connector corrosion first - VW connectors are notorious for this issue. If the module has failed, replacement requires VCDS or ODIS programming. After repairs, battery adaptation procedures may be needed to reestablish proper energy management parameters.