U3571Stack Outlet Coolant Temperature Sensor 1 Circuit
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3571 concerns the wiring and signal of sensor 1 in the coolant stream leaving the stack. Coolant is hottest here, so the reading serves as the main overheat guard: GM holds stack outlet temperature mainly with a three-port valve sending coolant past or through the radiator and shuts the stack off when coolant at this point gets too hot. A wrong outlet value can therefore force a needless shutdown or hide genuine overheating. GM cross-checks the sensor against end cell temperatures and treats it as suspect when it reads more than 3 °C above their average. Hyundai can fall back on the exhaust temperature of the air side as a stand-in. No public maker document names U3571. Warning and lower output follow; U3572 covers sensor 2 at this location, U3570 the inlet.
- What you may notice
- Fuel cell system warning, MIL on
- Power reduced or fuel cell system switched off as a precaution
- Outlet temperatures of sensor 1 and sensor 2 disagree in live data
- Likely causes
- LikelyOpen, short or corrosion in wiring or connector of outlet sensor 1
- PossibleOutlet temperature sensor 1 faulty internally or drifting
- RareConnector or wiring near the hot outlet line damaged by heat
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.