P0730Incorrect Gear Ratio
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0730 reports a wrong transmission ratio without assigning it to a gear. Two uses are documented. Older Aisin-type automatics (a 2006 GM table, Saab's 9-5 of 2002) set it when fourth or fifth gear shows the ratio of third – a shift solenoid (Saab: S3) is not switching; GM lights the MIL at once, Saab enters limp mode. GM's continuously variable transmissions of 2023 and 2025 use it when the pulleys do not reach the commanded variator ratio – the belt or chain slips or clamping pressure is too low – after one trip. Ford and newer GM step automatics use gear-specific or clutch valve codes instead. Check fluid level and condition first.
- What you may notice
- Slipping, engine speed rises without drive
- Wrong gear or missing upper gears, limp mode
- Check engine light (GM) or transmission warning
- CVT: judder, weak acceleration
- Likely causes
- LikelyFluid level or quality (CVT fluid or ATF)
- LikelyShift solenoid or pressure control valve sticking or faulty
- PossibleClutch or brake wear, or worn variator belt, chain or pulleys
- RareFaulty speed sensor signal
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €150 – €5,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.