P0731: Gear 1 Incorrect Ratio
What Does P0731 Mean?
P0731 is a diagnostic trouble code indicating: Gear 1 Incorrect Ratio. This code relates to the transmission system. It has been reported in NHTSA complaints across 5 different vehicle models.
The automatic transmission is controlled by the TCM using input from speed sensors, temperature sensors, and pressure sensors. When the TCM detects a fault, it may activate limp mode (2nd or 3rd gear only). Shift solenoids are electromagnetic valves inside the valve body controlling hydraulic fluid flow. Modern transmissions use 4-8 solenoids in combination for each gear. Solenoid failures are often caused by contaminated fluid — worn clutch material and degraded fluid create varnish that sticks solenoids. Always check transmission fluid first: level, color (red/pink good, brown/black bad), and smell (burnt = internal damage). Transmission DTCs escalate fast — a $200 solenoid fix can become a $3000-$5000 rebuild if ignored.
Symptoms of P0731
- ⚠️ Check engine/transmission warning light on
- ⚠️ Harsh, delayed, or erratic shifting
- ⚠️ Transmission stuck in one gear (limp mode)
- ⚠️ No upshift or no downshift
- ⚠️ Transmission slipping
- ⚠️ RPM flares between shifts
Common Causes
- 🔍 Faulty shift solenoid
- 🔍 Contaminated transmission fluid
- 🔍 Wiring issue between TCM and solenoid
- 🔍 Valve body wear
- 🔍 TCM internal failure
P0731 Reports by Year
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"The contact owns a 2014 Ford Escape. The contact stated that while driving at an undisclosed speed, she heard a humming noise and the vehicle inadvertently slowed down while the accelerator pedal was depressed. The contact stated that she was able to maneuver the vehicle off the road and placed the "
— Ford Escape owner, 09/26/2022
"VEHICLE WAS DRIVING ON INTERSTATE WHEN IT STARTED HESITATING AND RPMS REVVING UP AND DOWN CHAOTICALLY. NO CHECK ENGINE OR SERVICE LIGHTS WERE ON. VEHICLE TOWED HOME, AND DRIVEN TO DEALERSHIP NEXT DAY. SAME PROBLEM STARTED HAPPENING WHEN THE CHECK TRANSMISSION LIGHT CAME ON AND VEHICLE WOULD NOT MO"
— Ford Escape owner, 10/12/2020
"Vehicle warning indicated to restart car. Pulled over and car did not restart. Dealership indicated that the power steering belt broke the crank sensor on the motor and if the sensor was broke it would not start. They stated that they wouldn’t look for any other issues if it was the sensor that w"
— Ford Escape owner, 06/03/2022
Source: NHTSA Complaints Database
Most Reported Vehicles for P0731
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | FORD ESCAPE | |
| 2 | FORD MUSTANG | |
| 3 | FORD EXPLORER | |
| 4 | NISSAN ALTIMA | |
| 5 | DODGE JOURNEY |
P0731 Reports by Vehicle
Detailed NHTSA complaint analysis for each vehicle model.
Diagnostic Tips
- Check fluid level and condition FIRST
- Multiple codes suggest valve body or internal damage
- Monitor solenoid duty cycle with scan tool
- Solenoids often accessible by removing pan
Common Mistakes to Avoid
- ❌ Replacing solenoid without flushing contaminated fluid
- ❌ Using aftermarket fluid instead of manufacturer-specified
- ❌ Driving in limp mode for extended periods
Frequently Asked Questions
What is a shift solenoid?
Can I drive in limp mode?
How much for solenoid replacement?
Can fluid change fix it?
What To Do Next
Possible Fixes
- 🔧 Replace shift solenoid or pack
- 🔧 Transmission fluid flush with manufacturer fluid
- 🔧 Repair wiring to transmission
- 🔧 Replace valve body
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.