U3557Hydrogen Tank C Valve Enable Circuit
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3557 is stored for a fault in the enable circuit of the tank C valve, the third tank of three-tank vehicles. Permission to open is not tied to driving alone: a Honda patent describes the cutoff valve being open with the ignition off, for example when the stack keeps operating after shutdown, so collision detection stays powered in that state and a cutoff relay can still close the valve. The enable path therefore has to work when the car is parked, and faults may surface after switch-off. FMVSS 307 asks for valve closure within 5 seconds of any crash. No manufacturer documents U3557. Expect tank C to stay shut, a warning and less range. If U3551 and U3554 are also stored, look for a supply common to all valves.
- What you may notice
- Hydrogen system warning, possibly right after switch-off or at start
- Reduced range
- Likely causes
- PossibleCutoff or enable relay for valve C faulty
- PossibleFuse or common valve supply interrupted
- PossibleEnable line to tank C damaged
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.