What it means
Hydrogen Tank B Temperature Sensor 2 Circuit: an electrical fault is present in the circuit.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
Hydrogen tank B temperature sensor 2 monitors a second temperature point or channel associated with tank B. This code means the electrical circuit for sensor 2 is faulty, so its reading may be missing or unreliable even when tank B sensor 1 appears normal.
Common causes
Most likely first.
- Temperature sensor failed
- Gateway module routing CAN messages incorrectly
- CAN 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
How to diagnose it
- Scan all relevant modules and save freeze-frame data, checking whether U354D appears with other tank B sensor or communication faults.
- Review live data for tank B temperature sensor 2 and compare it with tank B sensor 1 and other available readings for dropouts or implausible values.
- Inspect the tank B sensor 2 connector and accessible wiring for poor seating, corrosion, moisture, or damage without disturbing hydrogen components.
- Measure sensor 2 circuit power, ground, signal, and continuity using the manufacturer's wiring diagram and specifications.
- If wiring is sound, test tank B temperature sensor 2 according to the manufacturer's procedure and investigate gateway or CAN communication only if indicated.
Common fixes
- Reconnect or clean a confirmed poor electrical connection at tank B temperature sensor 2.
- Repair damaged sensor 2 wiring or a verified power or ground fault.
- Replace tank B temperature sensor 2 if it fails the specified test with a sound circuit.
- Repair a confirmed gateway or network fault that interrupts sensor 2 data.
Can I keep driving?
The control system may not have a reliable tank B temperature sensor 2 reading while this fault is active. Stop safely if fuel-cell warnings, reduced power, or a shutdown warning appear, and follow the vehicle's instructions.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.