U3552Hydrogen Tank A Valve Performance
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- U3552 is the performance code for the valve on tank A: the circuit tests good, but the valve does not act as commanded, either staying shut or failing to seal. With several tanks this is hard to see, because one pressure sensor where the tank lines merge cannot tell that a single tank no longer delivers. Hyundai's answer in a 2018 patent is to estimate how much hydrogen is supplied and compare it with what the stack consumes and purges; another Hyundai patent, with a sensor on each tank, flags the tank whose pressure drifts about 50 bar from the rest. No maker documents U3552 publicly. The driver mainly notices less range and a warning, and the tank with the faulty valve is kept closed. U3555 is tank B.
- What you may notice
- Noticeably lower range than the gauge suggests
- Hydrogen system warning
- Likely causes
- PossibleTank A valve stuck closed or opening sluggishly
- RareValve seat no longer sealing
- RareImplausible tank pressure reading misleading the check
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €500 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.