Code result
U0637
Lost Communication With Hybrid/EV Battery Pack Coolant Control Valve B
High severity
What it means
The vehicle bus reports loss of communication with smart HV battery pack coolant control valve B. Coolant routing for the battery cooling loop cannot be commanded.
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
Bus wiring open or shorted
highOne of the most commonly reported causes for this code — check this first.
Module without power or ground
mediumA plausible cause — test and verify before replacing parts.
Module failed
mediumA plausible cause — test and verify before replacing parts.
Related help
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