P003B code meaning
Turbocharger/Supercharger Boost Control B Position Exceeded Learning Limit
Powertrain system Generic code P00xx codes Check engine light
What P003B means
The electric boost actuator B positions the variable turbine vanes or the wastegate and reports its position through a sensor. In a learning run, for example with the engine warm at idle or after switching off, the control module drives the actuator to its mechanical end stops and stores the sensor values as reference. P003B is set when a learned end position or the total travel lies outside the permitted limits. Typical reasons are worn or sticking vanes or linkage, a faulty actuator, a broken actuator lever, or a replacement actuator that has not been learned in. B denotes the second actuator, for example on the second stage of a two-stage system.
P003B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P003B
- Check engine light on
- Reduced power mode
- Underboost or overboost codes possible
- Sometimes no noticeable symptoms
Common causes of P003B
- Most likelyElectronic actuator or its control module faulty
- PossibleVane mechanism, sector gear or linkage worn or sticking
- PossibleReplacement not learned in, or learning run aborted (e.g. low voltage)
- Less likelyActuator lever broken
- Less likelyPosition sensor or its wiring faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Boost control actuator bActuator position sensorTurbocharger vanes or wastegate
What each part of P003B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| 3B | The exact fault in that area. |
What to do next
- Note P003B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P003B
What does P003B mean?
P003B means "Turbocharger/Supercharger Boost Control B Position Exceeded Learning Limit". The electric boost actuator B positions the variable turbine vanes or the wastegate and reports its position through a sensor. It is a generic code, so it means the same on every make.
Is it safe to drive with P003B?
Drive gently and only to a workshop. With P003B the car can go into limp mode (reduced power) to protect itself.
Will P003B fail an emissions test?
Yes, it can. P003B is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P003B to fix?
Difficulty: workshop only. A typical repair takes 1 to 3 hours of work. This is a job for a workshop.
Will P003B clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.