U3570Stack Inlet Coolant Temperature Sensor Circuit
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3570 signals that the sensor for coolant entering the stack sends a broken, shorted or out-of-range reading. Thermal control is steered by this value: Hyundai describes a three-port valve which gets the stack inlet temperature from the fuel cell control unit over CAN and sets its opening from it, and in a Nissan patent the current drawn from the stack is capped once inlet coolant passes a set point, so that the outlet cannot overheat. GM shows that the inlet figure can also be estimated from pump inlet temperature, flow rate and a heat exchanger model. No maker documents U3570 publicly. Without a valid reading the system has to run on a substitute; a warning lamp and held-back power are to be expected. Outlet sensors report as U3571 and U3572.
- What you may notice
- Fuel cell system warning, MIL on
- Reduced power, especially under high load
- Implausible stack inlet temperature in live data
- Likely causes
- LikelyOpen, short or corrosion in wiring or connector of the inlet sensor
- PossibleInlet coolant temperature sensor faulty internally (drift, internal open)
- RareCoolant seeping past the sensor seal into the connector
- RareInput stage of the fuel cell control unit faulty
- 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.