Engine Coolant Bypass Valve A Range/Performance
The coolant bypass valve A responds to commands but the resulting coolant temperature behaviour is not as expected. Possibly stuck partially open or contaminated bore.
Affected components
- Coolant bypass valve a
- Thermostat housing
Common causes
- High likelihood: Valve partially stuck by sediment
- Medium likelihood: Weak return spring fails to close fully
- Low likelihood: Sensor element aged beyond calibration window
Diagnostic notes
- The malfunction indicator lamp may illuminate
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.