U3564 code meaning
Hydrogen Supply Line A Pressure Sensor 1 Circuit
Network system Generic code U35xx codes Check engine light
What U3564 means
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.
U3564 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U3564
- Fuel cell system warning, MIL on
- Reduced power
- Fuel cell system may refuse to start
Common causes of U3564
- Most likelyOpen, short or corrosion in wiring or connector of pressure sensor 1
- PossiblePressure sensor 1 faulty internally (maker may supply a revised part)
- Less likely5 V supply or ground of the sensor missing
- Less likelyFuel cell control unit faulty or needing a software update
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
H2 supply a pressure sensor 1Sensor wiring
What each part of U3564 means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 64 | The exact fault in that area. |
What to do next
- Note U3564 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 U3564
What does U3564 mean?
U3564 means "Hydrogen Supply Line A Pressure Sensor 1 Circuit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with U3564?
Drive gently and only to a workshop. With U3564 the car can go into limp mode (reduced power) to protect itself.
Will U3564 fail an emissions test?
U3564 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 U3564 to fix?
Difficulty: workshop only. A typical repair takes 1 to 3 hours of work. This is a job for a workshop.
Will U3564 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.