U041AInvalid Data Received From Battery Isolation/Voltage Stabilization Control Module
- Generic OBD-II code · Network
- How the car detects it
- U041A refers to the battery isolation or voltage stabilization module, which separates an auxiliary battery or sensitive loads from the starter circuit, so a restart after an automatic engine stop leaves the rest of the electrical system at stable voltage. GM's patent US 9,803,608 builds such an isolator from MOSFET switches. A receiver logs it once the module's status frames still arrive but are rejected as invalid. No manufacturer documents U041A publicly. Ford shows the module family on the 2021-2022 F-150 3.5 L PowerBoost, where lost contact (U061E) turns on the wrench lamp and a weak ground GD132 or a failed auxiliary battery isolator is blamed (SSM 50843); checking ground and auxiliary battery first makes sense for U041A as well. Expect stop-start to be disabled; a MIL is unlikely.
- What you may notice
- Automatic stop-start not available
- Battery or charging system message
- Likely causes
- PossiblePoor ground connection of the isolation module
- PossibleWeak auxiliary battery making the module report implausible values
- RareBattery isolator or stabilizer internally faulty
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.