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

P0826

Up and Down Shift Switch Circuit

The TCM detects a fault in the combined up/down shift switch circuit, where both switch states are simultaneously active or both inactive when activity is expected.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number8 / 26

Possible causes

  • Switch internal short high
  • Wiring shorted between channels 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: easy
  • DIY: possible
  • Estimated cost: 80–350 €
  • Estimated time: 0.3–1.5 h
  • Component: shift switch assembly
  • Component: wiring harness
  • MIL / check engine light

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