P056FCold Start Turbocharger/Supercharger Boost Control B Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- CARB requires every element commanded by the cold-start strategy to respond measurably in the commanded direction, with its own codes separate from the general monitoring of the same part. During catalyst heating the boost control is positioned deliberately – diesels close the variable turbine for load and heat, petrol engines open the wastegate so heat reaches the catalyst. P056F is the same check for boost control B – a second charger on twin-turbo or sequential systems, or a second stage. No manufacturer document available to us uses P056F; the Ram 6.7 L with a single charger only lists P056E. The description follows CARB's cold-start rules.
- What you may notice
- Check engine light on
- Rough cold running
- Otherwise usually unremarkable
- Likely causes
- LikelyCharger B actuator stiff or faulty
- PossibleVacuum or charge air line of charger B leaking
- PossibleSoftware or calibration
- RareBoost or position sensor B
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €0 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.