Network, generic (extended)

U3553 Hydrogen Tank B Valve Control Circuit

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U3553 means the controller sees a fault in the drive circuit of the solenoid valve on tank B, such as an open coil, a short to ground or supply, or an output that does not follow its command. Hyundai shows in a patent how such valves can be checked: one current sensor reads the operating current of several tank solenoids; if it falls below a reference, the controller switches the PWM duty from 100 to 90 % and looks whether the fed-back duty appears inverted. If not, the valve is judged faulty. In the workshop that means measuring coil resistance and following the harness from tank to controller. No maker documents U3553. Until repaired, tank B stays closed; U3550 and U3556 are the same fault on tanks A and C.

Likely causes

Damaged wiring or corroded connector to the tank B valve
Solenoid coil open or shorted
Output stage of the control unit faulty

Symptoms

  • Hydrogen system warning
  • Range reduced because tank B is not used

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–5,000
Time1–8 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

h2 tank b valvevalve wiring

Related codes

U3554U3555U3550U3556

References: patents.google.com, law.cornell.edu.