The U3570 code indicates that the vehicle's control module has detected an electrical anomaly in the circuit for the coolant temperature sensor located at the inlet of the power stack (such as a fuel cell or high-voltage battery). This means the system cannot accurately read the temperature of the coolant entering the stack, which is critical for proper thermal management and safe operation.
The sensor itself may have an internal failure, causing it to send out-of-range or no signal to the control module.
Corroded, frayed, or disconnected wiring and poor pin contacts at the sensor connector are common causes of circuit codes.
Insufficient coolant or trapped air around the sensor can prevent it from reading accurately, triggering a circuit or range code.
In rare cases, the control module may have outdated or corrupted software causing it to misinterpret the sensor signal.
Internal failures within the control module are extremely rare and should only be considered after all other possibilities are eliminated.
It is not recommended. Without accurate temperature data, the thermal management system may not cool the stack properly, which can lead to severe and expensive damage to the fuel cell or high-voltage battery.
No, that is a common misdiagnosis. The code almost always points to a failed sensor, wiring issue, or coolant problem. Replacing the control module is rarely the correct fix and should only be done as an absolute last resort.
In this context, 'stack' typically refers to a fuel cell stack or a high-voltage battery pack. These components require precise, active liquid cooling to operate safely and efficiently.
Yes. If the coolant level is low, air pockets can form around the sensor. Since the sensor relies on the coolant to absorb its heat, an air pocket will cause erratic readings and trigger the code.