Code result
P0E77
Coolant Bypass Valve B Control Circuit/Open
High severity
What it means
The coolant bypass valve B reports a control circuit/open condition.
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
Open in control wire
highOne of the most commonly reported causes for this code — check this first.
Coil open
mediumA plausible cause — test and verify before replacing parts.
Pin pushed back out of connector body
lowLess common, but worth ruling out after the more likely causes.
Related help
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