U3530High Voltage System Interlock Circuit J High
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3530 flags loop J above its upper threshold. Foreign voltage is one explanation, but in a design that pushes a constant current through the loop and reads the drop across it, any added resistance lifts the measured value too. Tesla's HVIL tech note for early Model S cars, filed with NHTSA, names a poor solder joint at a charger board connector that exceeded 90 ohms only when hot. To reproduce it, technicians drove about 20 minutes at highway speed, charged for at least half an hour and measured the loop pins on the still warm charger. A loop J fault that turns up only after long trips or charging sessions points to such heat-sensitive joints. No maker documents U3530 itself.
- What you may notice
- Fault appears after long drives or charging, not on a cold start
- Charging session or drive interrupted by a high-voltage warning
- Loop measures normal once the components have cooled down
- Likely causes
- PossibleCracked solder joint or crimp in loop J whose resistance rises when warm
- PossibleLoop J wire in contact with a 12 V supply
- PossibleLoose or spread terminal in a loop J connector
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.