U3576Stack Differential Pressure Sensor Circuit
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3576 is set when the stack differential pressure sensor delivers no signal, a shorted one or one outside its valid range. The title leaves open which two pressures it compares. In a GM patent such a sensor is plumbed between anode and cathode side, as the anode is normally kept slightly above the cathode. GM also uses it ahead of start-up, with the cathode still at ambient pressure, to verify the anode pressure sensor: ambient plus differential reading should match the anode value. Ford keeps the difference across the membrane within a tolerance of around 600 mbar, may shut the system down when it is breached and heats such sensors so that ice cannot blind them. No maker documents U3576 publicly. Expect a warning, reduced power or no start; anode inlet pressure is U3566/U3567.
- What you may notice
- Fuel cell system warning, MIL on
- Reduced power or fuel cell system shuts down
- No start, especially after a cold night
- Likely causes
- LikelyOpen, short or corrosion in wiring or connector of the differential pressure sensor
- PossibleWater or ice in the sensor ports or a failed sensor heater
- PossibleDifferential pressure sensor faulty internally
- Repair
- Hard · Usually a job for a workshop.Typical cost: €150 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.