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

P0909

Gate Select Control Error

The TCM detects that the gate select actuator does not reach the commanded position within tolerance. Mechanical bind, weak actuator, or sensor offset.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number9 / 09

Possible causes

  • Selector mechanism binding high
  • Actuator force degraded medium

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: 400–2000 €
  • Estimated time: 2–7 h
  • Component: gate select actuator
  • Component: gate select 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