P0730Incorrect Gear Ratio
What it means
In a gear the ratio between input and output shaft speeds is not what it should be. The transmission is slipping, or one of the speed signals is wrong.
Symptoms
- Engine revs rise without the car speeding up (slipping)
- Harsh or delayed shifts
- Limp mode
Common causes
- Low or burnt transmission fluid
- Worn clutch packs or bands
- Faulty input or output speed sensor
- Internal hydraulic leak or valve body fault
What to check first
- Check fluid level and condition
- Compare input, output and engine speed in live data
- Look for metal or friction material in the pan
Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.