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

P0102

Mass or Volume Air Flow Circuit Low Input

The MAF sensor reports an air flow value below the plausible minimum for current engine speed and load. The ECU substitutes a calculated load value while the fault is active.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 02

Possible causes

  • MAF sensor failed high
  • MAF connector loose or disconnected medium
  • Signal wire shorted to ground low

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 80–300 €
  • Estimated time: 0.3–1.5 h
  • Component: mass air flow sensor
  • Component: intake duct
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required

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