P0730
Incorrect Gear Ratio
Automatic transmission
Generic OBD-II
High
What it means
P0730 means the transmission controller has compared input and output speeds and found the gear ratio doesn't match the gear it commanded — the transmission is effectively slipping or not engaging the right gear. Common causes range from low fluid or a bad solenoid to internal wear, and continued driving while it slips generates heat and risks further damage.
High
Can I keep driving? Cautiously — slipping or a wrong gear ratio strains the transmission and can worsen; drive gently and get it checked promptly.
Common symptoms
What you'll notice
- Check-engine light on
- Transmission slipping or engine revving without matching acceleration
- Harsh, delayed, or wrong-gear shifting
- Transmission running hot
Common causes
Most likely first
- Low or contaminated transmission fluidLikely
- Faulty shift or pressure-control solenoidCommon
- Worn clutches, bands, or internal transmission wearCommon
- Failing torque converter or input/output speed sensor mismatchLess often
How to diagnose & fix
Work through it in order
- Scan and read freeze-frame; check for accompanying solenoid or speed-sensor codes.
- Check the transmission fluid level and condition first — low or burnt fluid is a common cause.
- Test the shift and pressure-control solenoids and the speed sensors.
- If the ratio is still wrong, the transmission likely needs internal inspection or service. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0730?+
Only gently and briefly. A wrong gear ratio usually means the transmission is slipping, which generates heat and can cause further damage. Get it diagnosed soon.
Can I just clear P0730?+
It returns as soon as the transmission slips again; clearing it doesn't fix the underlying fluid, solenoid, or mechanical problem.
Related codes
Often seen with P0730
Read & clear P0730 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX