U3027Control Module A Disable Circuit High
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U3027 is the high-side counterpart: the disable line to module A reads above its valid range, as with a short to battery voltage or a neighbouring wire. In an active-low design such as the one in Siemens patent US7596436B2, where pulling the shutdown path to ground blocks the output stages, a line stuck high means module A keeps its enable and can no longer be switched off over the hard-wired path. That removes the independent safety layer FCA's patent US10676100B2 is built around, where losing a shutoff line could let a hybrid keep producing torque. Systems therefore treat this case strictly and usually disable the function by other means. No manufacturer documents U3027 publicly; check for a short to a powered wire in the harness and for water in connectors.
- What you may notice
- Function locked out by the safety concept, system warning shown
- Vehicle may not become ready to drive
- Likely causes
- LikelyDisable wire shorted to a battery or supply wire
- PossibleMoisture or corrosion bridging pins in a connector
- RareOutput driver of the supervising module stuck high
- Repair
- Hard · Usually a job for a workshop.Typical cost: €50 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.