Network, generic (extended)

U3568 Anode Multifunction Valve Control Circuit

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Open, short or corrosion in wiring or connector of the valve (wet area below the stack)
Solenoid coil of the valve open or shorted
Driver stage of the fuel cell control unit faulty

Symptoms

  • Fuel cell system warning, MIL on
  • Power dropping off the longer the drive lasts
  • Fuel cell system shuts down or does not start

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–1,200
Time0.5–3 h

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

Parts involved

anode multifunction valvevalve wiring

Related codes

U3569U356AU356CU3566

References: patents.google.com, patents.google.com.