Code result
P26AB
Engine Coolant Bypass Valve A Stuck/Open
Moderate severity
What it means
The coolant bypass valve A is stuck in the open position. Coolant always bypasses the radiator, leading to overheating under load.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Valve seized open by sediment or wax
highOne of the most commonly reported causes for this code — check this first.
Broken return spring
mediumA plausible cause — test and verify before replacing parts.
Related help
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