U355D

Expander Inlet Pressure Sensor 1 Circuit

Moderate severity

Generic fault on the inlet pressure sensor 1 of the expander (turbine recovering energy from the cathode exhaust on FCEVs).

Common causes

Sensor failed
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $220-1650
Gateway module routing CAN messages incorrectly
Less common, but worth ruling out after the more likely causes.
low
Typical part cost: $220-1650
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First things to check

1Confirm the code with a scan tool and check for additional related codes.
2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

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Related codes

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Frequently asked questions

What does U355D mean?

U355D means "Expander Inlet Pressure Sensor 1 Circuit". It is a generic OBD-II code that points to a fault in the network / communication.

What are the most common causes of U355D?

sensor failed; gateway module routing can messages incorrectly; can terminating resistor (120 ω) drifted out of spec — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.

Can I keep driving with this code?

The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.

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