OBD-II code · Powertrain (generic)
P0729 Gear 6 Incorrect Ratio
When gear 6 is engaged, the measured ratio between the input- and output-shaft speed sensors does not match the expected ratio for that gear. This means the transmission is slipping in gear 6 rather than transmitting power solidly. Causes: worn clutch packs or bands, low fluid level or pressure, a stuck shift solenoid, or a valve-body fault affecting gear 6.
Is it safe to drive with P0729?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyShift solenoid stuck
- PossibleClutch pack worn or slipping
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
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1.5–12 h
- Emissions test
- Usually unaffected
- Parts involved
- Automatic Transmission, Shift Solenoid
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.