U355ACharge Air Cooler Outlet Pressure Sensor 1 Circuit
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U355A concerns the first of two pressure sensors behind the charge air cooler, where compressed and cooled air heads for the humidifier and the stack. This is the pressure the system really regulates: in a Nissan patent a sensor between intercooler and water recovery unit is the feedback for compressor torque and the outlet pressure valve, and the controller caps this pressure so that compressor and humidifier stay below their heat limits. Toyota takes its counterpart behind compressor and intercooler as the delivery pressure for the surge check. No public manufacturer document names U355A. An open or shorted circuit takes away the main pressure feedback; expect a fuel cell warning and reduced output. Where sensor 2 (U355B) is fitted it can serve as a fallback.
- What you may notice
- Fuel cell system warning, MIL on
- Noticeably reduced power
- Compressor speed fluctuates or stays high
- Likely causes
- LikelyOpen, short or corrosion in wiring or connector of sensor 1
- PossiblePressure sensor 1 faulty internally
- RareShared 5 V supply or ground faulty (often with other sensor codes)
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.