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

P28FA

Exhaust Pressure Too Low Bank 2

The exhaust pressure measured on bank 2 falls below the calibrated minimum. Common causes are leaks upstream of the sensor, missing DPF substrate, or sensor calibration drift.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number8 / FA

Possible causes

  • Exhaust leak upstream of sensor high
  • Sensor zero point drifted medium

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 200–2500 €
  • Estimated time: 1–8 h
  • Component: exhaust pressure sensor b2
  • Component: particulate filter
  • Component: exhaust system
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required
  • limp mode possible

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