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

P28E9

Shift Motor Position Sensor Circuit Low

Voltage on the shift motor position sensor signal line is below the expected window. Wire shorted to ground or sensor short.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number8 / E9

Possible causes

  • Signal wire shorted to ground high
  • Internal sensor short medium
  • Connector pins corroded - high contact resistance low

Symptoms

  • Check engine or transmission warning light on
  • Harsh, delayed, or missing shifts
  • Possible limp mode (locked in one gear)
  • Slipping or shuddering during gear changes

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 400–2200 €
  • Estimated time: 2–8 h
  • Component: shift motor
  • Component: shift motor position sensor
  • Component: tcm
  • MIL / check engine light
  • 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