Powertrain
Definition only
Lights the check engine lamp
P26AB: Engine Coolant Bypass Valve A Stuck/Open
Standardized SAE J2012 code · P26xx — Computer and output circuits
What does P26AB mean?
The coolant bypass valve A is stuck in the open position. Coolant always bypasses the radiator, leading to overheating under load.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Valve seized open by sediment or wax
- Medium Broken return spring
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P26AB on the same make and model first.
P26AB in the community
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