P0730 Incorrect gear ratio
What P0730 means
The transmission control unit compares input and output shaft speeds and has found a ratio that does not match the gear it selected. This usually means clutches inside the gearbox are slipping.
P0730 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- High
- Typical repair cost
- 150–3000 €
- Workshop time
- 2–12 h
- Repair difficulty
- Hard
- DIY possible
- No
- Check engine light
- Yes
- Affects emissions test
- No
- Limp mode possible
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Engine revs rising without the car accelerating
- Delayed or harsh shifts
- Limp mode stuck in one gear
- Transmission warning on
Common causes
- Low or degraded transmission fluid
- Faulty shift solenoid or valve body
- Worn clutch packs or bands
- Blocked transmission filter
- Faulty input or output speed sensor
Can I keep driving with P0730?
Have it checked within a day or two and drive as little as possible. Driving with a slipping automatic gearbox can quickly destroy it.
What to check first
- Check the transmission fluid level and condition (burnt smell or dark colour)
- Check for other transmission codes such as speed sensor or solenoid faults
- Have the fluid and filter changed if appropriate
- Have the gearbox pressure-tested and inspected for internal wear
Related codes
- P0731 Gear 1 incorrect ratio
- P0732 Gear 2 incorrect ratio
- P0733 Gear 3 incorrect ratio
- P0734 Gear 4 incorrect ratio
- P0735 Gear 5 incorrect ratio
- P0722 Output shaft speed sensor no signal
- P0720 Output shaft speed sensor circuit
- P0740 Torque converter clutch circuit/open
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
Updated: