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

P28BE

Cylinder 12 Ion Current Sense Circuit Low

Ion current from cylinder 12 is below the expected window. Spark plug fouled, signal wire shorted to ground, or sensing path interrupted.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number8 / BE

Possible causes

  • Spark plug fouled with carbon or oil high
  • Sense wire shorted to ground medium
  • Connector pins corroded - high contact resistance low

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 100–700 €
  • Estimated time: 0.5–3 h
  • Component: spark plug cyl 12
  • Component: ignition coil cyl 12
  • Component: ion sense module
  • 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