P0731 Gear 1 incorrect ratio
What P0731 means
The transmission control unit has found that input and output shaft speeds in first gear do not match the expected ratio. The clutch or band that holds first gear is likely slipping.
P0731 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
- 500–4000 €
- Workshop time
- 4–16 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 flaring when pulling away
- Slow or weak acceleration from a stop
- Harsh or delayed shift into 1st
- Limp mode
Common causes
- Low or degraded transmission fluid
- Worn first-gear clutch pack or band
- Faulty shift solenoid or valve body
- Low line pressure from a worn pump or blocked filter
Can I keep driving with P0731?
Have it checked within a day or two and avoid hard acceleration. Continued driving with a slipping gear can destroy the gearbox.
What to check first
- Check transmission fluid level and condition
- Look for other codes such as solenoid or pressure faults
- Change fluid and filter if it is old or low, then retest
- Have line pressure tested and the gearbox inspected for internal wear
Related codes
- P0730 Incorrect gear 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
- P0740 Torque converter clutch circuit/open
- P0741 Torque converter clutch circuit performance/stuck off
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: