P0731 Code: Gear 1 Incorrect Ratio
🟠 Moderate severity · drivable
Drivable, but first gear is slipping, which can cause serious damage if ignored.
What P0731 means
The transmission is slipping in first gear — the actual gear ratio doesn't match what the computer commanded.
Symptoms
- Check engine light is on
- Slipping in first gear
- Harsh or delayed 1-2 shift
- Reduced acceleration from a stop
Common causes
- most common: Low or dirty transmission fluid
- common: Worn first-gear clutches or bands
- common: Faulty shift solenoid or valve body
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Check and change the transmission fluid and filter | Yes | $100–250 |
| Repair internal transmission slippage | Mechanic | $1500–4000 |
Frequently asked questions
Can I drive with a P0731 code?
Yes, but first gear is slipping, which can cause serious damage. Get it checked promptly.
What is the most common cause of P0731?
Low or dirty transmission fluid, or worn first-gear clutches.
How much does it cost to fix a P0731?
A fluid change is $100–$250; a rebuild runs $1,500–$4,000.
Related codes
P0730
P0730 Code: Incorrect Gear Ratio
P0732P0732 Code: Gear 2 Incorrect Ratio
P0700P0700 Code: Transmission Control System Malfunction
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.