U355DExpander Inlet Pressure Sensor 1 Circuit
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U355D covers the first pressure sensor in front of the expander, a turbine in the cathode exhaust that turns leftover pressure from the stack outlet into shaft power for the compressor. Garrett states that its optional turbine expander, developed among others for the compressor of the BMW iX5 Hydrogen, lowers the electricity needed for compression by up to 20 %. In a Toyota patent a waste gate valve divides exhaust between turbine and bypass, because the flow resistance of the turbine raises the pressure the compressor must supply and can push it toward surge. A sensor at the turbine inlet shows this back pressure directly. No maker documents U355D. Losing it takes an input from energy recovery and cathode pressure control. Toyota's Mirai bulletin T-SB-0043-23 shows that faults on the cathode air side light the MIL.
- What you may notice
- Fuel cell system warning, MIL on
- Higher hydrogen consumption because less energy is recovered
- Reduced peak power
- Likely causes
- LikelyWiring or connector of sensor 1 at the wet exhaust side corroded, open or shorted
- PossibleExpander inlet pressure sensor 1 faulty internally
- RareSensor supply or ground faulty
- 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.