OBD Codes List

Diagnostic reference · P0729

P0729

Gear 6 Incorrect Ratio

System
Transmission (P code)
Lamp
Check Engine Light
Category
Powertrain - Transmission

What it means

P0729 means Gear 6 Incorrect Ratio.

Check these first

  • Low or degraded transmission fluid
  • A slipping clutch pack for sixth gear
  • A failing output or speed sensor
  • A worn gear set or bearing
  • A TCM calibration problem

What to do next

  1. Check the fluid level and condition first
  2. Compare input and output speed on a scan tool
  3. Read the commanded and actual ratio for sixth
  4. Inspect the speed sensors for debris
  5. Service the fluid and filter if it is dirty
  6. Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.