Incorrect gear ratio
What P0730 means
Your car's computer set P0730: Incorrect gear ratio. It belongs to the transmission group of codes. It is a generic code, so it means the same thing on every make. The check engine light usually comes on once the fault has been seen on two drives in a row. Until then it shows up as a pending code.
Can I keep driving? Get it checked soon. Driving a slipping transmission makes the damage worse.
Common causes
- Low or old transmission fluid
- Failed shift or torque converter solenoid
- Wiring problem
- Internal transmission wear
Fix the cheapest, most likely cause first. Clearing the code without a repair only turns the light off until the fault comes back.
Check it yourself
Check the fluid. Note when it happens (cold or hot, which gear) to help a shop.
Torque Deck reads P0730 with a cheap Bluetooth OBD2 adapter. It also shows the freeze frame (engine conditions at the moment the code set) and the live data you need to narrow it down.
Related codes
This page explains what the code usually means. It is not a diagnosis of your car. When in doubt, ask a mechanic.