P004B
Turbocharger/Supercharger Boost Control B Circuit Range/Performance
Boost control B mechanical/hydraulic deviation from target. Same as P0046 on actuator B. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
Boost control B mechanical/hydraulic deviation from target. Same as P0046 on actuator B. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
Common causes
- high
Vacuum/boost line leak
One of the most commonly reported causes for this code — check this first.
Typical part cost: $130-1650
- low
Sensor element aged beyond calibration window
Less common, but worth ruling out after the more likely causes.
Typical part cost: $130-1650
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does P004B mean?
P004B means "Turbocharger/Supercharger Boost Control B Circuit Range/Performance". It is a generic OBD-II code that points to a fault in the fuel & air metering / auxiliary emission controls.
What are the most common causes of P004B?
vacuum/boost line leak; sensor element aged beyond calibration window; sensor mounting loose - signal damping — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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