What it means
Same condition as the turbo A excessive-warm-up fault, applied to the second turbo. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Turbocharger B's boost control begins in open loop and switches to feedback control once position information is usable. This code sets when that transition takes too long, indicating a slow B-side actuator or position signal, or sticking vanes or wastegate; the code alone does not establish the vehicle's turbo layout.
Common causes
Most likely first.
- Turbocharger B vanes or wastegate sticking
- Boost-control actuator or linkage binding
- Position sensor or feedback signal out of range
Symptoms
- Check-engine light may come on
- Reduced engine power or boost may occur
How to diagnose it
- Save freeze-frame data and monitor commanded and actual turbo B position and boost readings from start-up to establish when feedback becomes stable.
- Inspect turbo B's actuator wiring, connector, and any control hoses for damage, poor contact, or leaks.
- Check the B-side actuator and linkage for binding and verify that the wastegate or vanes can move through their range.
- Use a supported actuator test, if available, and observe whether turbo B follows commands promptly and smoothly.
- Test the B-side position sensor signal against the manufacturer's specification, then inspect the mechanism for sticking if the feedback circuit is sound.
Common fixes
- Repair leaks or damaged connections in turbo B's actuator control hoses, if fitted.
- Repair poor contact or wiring faults in the B-side position feedback circuit.
- Free or service a sticking turbo B wastegate, vanes, or linkage using the manufacturer's procedure.
- Replace a confirmed sluggish B-side actuator or position sensor.
Can I keep driving?
Avoid hard acceleration and towing until turbo B responds normally, as boost may be limited and the engine may lose power. Stop if you notice a sharp power loss, heavy smoke, or unusual turbo noise.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.