U355CCharge Air Cooler Outlet Temperature Sensor Circuit
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U355C reports a circuit fault on the temperature sensor behind the charge air cooler. Compression heats the air strongly: Honda gives about 120 °C at the compressor outlet, while the stack works at 80 to 90 °C, so the air is first brought down to roughly 60 to 75 °C. The sensor confirms this cooling before the air reaches the humidifier. In a Toyota patent it sits between intercooler and humidifier, and if the intercooler coolant pump fails, the controller slows the compressor to keep air temperature below a set limit; Nissan derives an upper pressure limit from the same reading. No maker documents U355C publicly. Without a valid temperature, humidifier and membrane lose their protection, so a warning and a careful cut in power should follow. Pressure here is U355A/U355B.
- What you may notice
- Fuel cell system warning, MIL on
- Power limited, especially under sustained high load
- Compressor runs at reduced speed
- Likely causes
- LikelyOpen or short in wiring or connector of the temperature sensor
- PossibleTemperature sensor (thermistor) faulty internally
- RareSensor ground or reference circuit faulty
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €80 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.