OBD-II code · Network (extended)
U3554 Hydrogen Tank B Valve Enable Circuit
Hydrogen Tank B Valve Enable Circuit: an electrical fault is present in the circuit.
Is it safe to drive with U3554?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyEnable wire open or relay failed
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Usually unaffected
- Parts involved
- H2 Tank B Valve Enable, Safety Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.