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U3564 Hydrogen Supply Line A Pressure Sensor 1 Circuit

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U3564 deals with the wiring of pressure sensor 1 on hydrogen supply line A, most likely the medium-pressure section behind the tank regulator; J2012 does not fix the spot. Toyota's patent shows such a layout: a mechanical reducing valve brings tank hydrogen down to roughly 1.1–1.6 MPa, an intermediate pressure sensor watches that section, and the injector then lowers the pressure to about 200–300 kPa for the stack. To find an offset, Toyota closes the tank valve, lets the injector draw the line down until the reducer stands wide open, and compares readings up- and downstream of it. Hyundai's Nexo has two hydrogen pressure sensors, numbered 1 and 2, with their own codes (P315200/P315300) and renewed both in campaign T4E; U3564 itself is in no public document. Without the value, regulator monitoring suffers and power may be limited.

Likely causes

Open, short or corrosion in wiring or connector of pressure sensor 1
Pressure sensor 1 faulty internally (maker may supply a revised part)
5 V supply or ground of the sensor missing
Fuel cell control unit faulty or needing a software update

Symptoms

  • Fuel cell system warning, MIL on
  • Reduced power
  • Fuel cell system may refuse to start

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€200–1,200
Time1–3 h

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

Parts involved

h2 supply a pressure sensor 1sensor wiring

Related codes

U3565U3549U3566U3550

References: patents.google.com, static.nhtsa.gov.