Code result
U3561
Cathode Bypass Valve Control Circuit
High severity
What it means
Generic electrical fault on the cathode bypass valve control. Bypass routes air around the stack during startup or low-load operation.
Is it safe to drive?
No — stop driving
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.
Most likely causes
Valve actuator failed
highOne of the most commonly reported causes for this code — check this first.
Gateway module routing CAN messages incorrectly
lowLess common, but worth ruling out after the more likely causes.
CAN terminating resistor (120 Ω) drifted out of spec
lowLess common, but worth ruling out after the more likely causes.
Related help
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