OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P056F

Cold Start Turbocharger Boost Control B Performance

During cold-start the ECU runs an elevated boost target on the A turbo to support catalyst heat-up and cold-running combustion stability. The actual boost does not reach the cold-start target - typically a wastegate or VGT actuator sticking when cold.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number5 / 6F

Possible causes

  • Actuator sticking when cold high

Symptoms

  • Charge status indicator shows fault
  • Charging may not start or interrupts
  • Slower-than-expected charge rate

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 200–1500 €
  • Estimated time: 1.5–5 h
  • Component: turbocharger b
  • Component: wastegate b
  • Component: vgt actuator b
  • MIL / check engine light
  • emissions-relevant

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication