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

P25FF

Electrical System Voltage Stabilizer Control Module Performance

The voltage stabiliser module (DC/DC converter for stop-start engine cranking events) does not maintain the regulated 12 V output during high transient loads. Sensitive electronics may reset during cranking.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / FF

Possible causes

  • Aged smoothing capacitors lose capacitance high
  • Battery condition causes input voltage to drop too far medium
  • Internal fault in the converter switching stage medium

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 200–1200 €
  • Estimated time: 1–3.5 h
  • Component: voltage stabilizer module
  • Component: dc dc converter
  • MIL / check engine light

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