What it means
Hydrogen Tank A 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 A temperature sensor 2 monitors a second temperature point or channel associated with tank A. This code indicates an electrical fault in sensor 2's circuit, so the control module may lose or distrust that sensor's signal even if tank A sensor 1 still reports normally.
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 record freeze-frame data, checking whether U354B is isolated or accompanied by a separate tank A sensor 1 or network fault.
- Review live data for tank A temperature sensor 2 and compare it with tank A sensor 1 and other available temperature readings for a missing or implausible value.
- Inspect the tank A sensor 2 connector and accessible harness for damage, loose fit, corrosion, or moisture, taking care not to disturb hydrogen components.
- Check sensor 2 circuit power, ground, signal, and continuity using the vehicle manufacturer's diagram and specifications.
- If the circuit is intact, test tank A temperature sensor 2 to the manufacturer's procedure and then check gateway or CAN communication if needed.
Common fixes
- Reconnect or clean a confirmed poor connection at tank A temperature sensor 2.
- Repair damaged sensor 2 wiring or a verified power or ground problem.
- Replace tank A temperature sensor 2 if it fails the manufacturer's test with a sound circuit.
- Repair a confirmed gateway or network fault affecting sensor 2 data.
Can I keep driving?
The code can leave the vehicle without a reliable reading from tank A temperature sensor 2, even if sensor 1 still works. If fuel-cell warnings, reduced power, or shutdown warnings occur, stop safely 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.