U3568 code meaning
Anode Multifunction Valve Control Circuit
Network system Generic code U35xx codes Check engine light
What U3568 means
U3568 flags trouble in the electrical drive of the anode multifunction valve: an open wire, a short against ground or battery voltage, or a failed output stage. The code title does not say which duties the valve combines; known designs merge draining water and purging nitrogen in one solenoid below the anode water separator. GM routes such a combined valve into the cathode inlet so that escaping hydrogen reacts on the catalyst, and Hyundai calls its version an integrated discharge valve. If the controller cannot switch it, the anode loses both its water outlet and its nitrogen outlet; in Hyundai's patent the system stops when no gas leaves the valve. No manufacturer documents U3568 publicly. A fuel cell warning with lost drive power is the likely result. Mechanical misbehaviour of the valve is U3569.
U3568 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U3568
- Fuel cell system warning, MIL on
- Power dropping off the longer the drive lasts
- Fuel cell system shuts down or does not start
Common causes of U3568
- Most likelyOpen, short or corrosion in wiring or connector of the valve (wet area below the stack)
- PossibleSolenoid coil of the valve open or shorted
- Less likelyDriver stage of the fuel cell control unit faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Anode multifunction valveValve wiring
What each part of U3568 means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 68 | The exact fault in that area. |
What to do next
- Note U3568 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 U3568
What does U3568 mean?
U3568 means "Anode Multifunction Valve Control Circuit". U3568 flags trouble in the electrical drive of the anode multifunction valve: an open wire, a short against ground or battery voltage, or a failed output stage. It is a generic code, so it means the same on every make.
Is it safe to drive with U3568?
Drive gently and only to a workshop. With U3568 the car can go into limp mode (reduced power) to protect itself.
Will U3568 fail an emissions test?
U3568 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 U3568 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U3568 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.