U3528High Voltage System Interlock Circuit G High
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3528 means something lifts loop G to a level the controller never expects from it. Texas Instruments notes that automotive interlocks, unlike industrial ones, must survive a short to the 12 V battery and to ground; its reference design feeds the loop through an intelligent switch on the supply side with current limiting and thermal shutdown. Such electronics may come through a short undamaged, whereas a simpler output stage can fail, and then the code returns even after the wiring is repaired because the driver now stays on. No manufacturer documents U3528. Remove the foreign voltage, clear the code and test again before replacing a controller.
- What you may notice
- No ready mode, high-voltage warning
- Code persists after the harness repair
- Likely causes
- LikelyLoop G wire shorted to the 12 V supply
- PossibleLoop output stage damaged by an earlier short and stuck on
- RareMoisture bridging pins in a loop G connector
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.