U3552 code meaning
Hydrogen Tank A Valve Performance
Network system Generic code U35xx codes Check engine light
What U3552 means
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.
U3552 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor2 to 10 hours
- Clears after repairAfter a drive cycle
Symptoms of U3552
- Noticeably lower range than the gauge suggests
- Hydrogen system warning
Common causes of U3552
- PossibleTank A valve stuck closed or opening sluggishly
- Less likelyValve seat no longer sealing
- Less likelyImplausible tank pressure reading misleading the check
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
H2 tank a valve
What each part of U3552 means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 52 | The exact fault in that area. |
What to do next
- Note U3552 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U3552
What does U3552 mean?
U3552 means "Hydrogen Tank A Valve Performance". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with U3552?
Drive gently and only to a workshop. With U3552 the car can go into limp mode (reduced power) to protect itself.
Will U3552 fail an emissions test?
U3552 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U3552 to fix?
Difficulty: workshop only. A typical repair takes 2 to 10 hours of work. This is a job for a workshop.
Will U3552 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.