U3522High Voltage System Interlock Circuit F Performance
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3522 is set when loop F behaves inconsistently, for instance when redundant evaluation channels reach different verdicts or the signal timing is off. Such checks exist because the interlock belongs to a safety function: Samsung SDI notes that it then needs an ASIL rating and failure-rate figures for its parts, so hidden faults in the monitoring path have to be caught, not just an open loop. CARB counts the interlock among safety-only systems, which is why this code concerns electrical safety rather than emissions and why lamp behaviour differs between makers. No manufacturer publishes U3522. Expect sporadic refusals to become ready.
- What you may notice
- Ready mode occasionally refused, then available again
- High-voltage warning that comes and goes
- Likely causes
- PossibleRedundant measuring channels for loop F disagree because of a sensing fault
- PossibleIntermittent contact in a loop F connector
- RareInternal fault of the evaluating controller
- 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.