P0731: Gear 1 Incorrect Ratio
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Drive gently to a shop - ratio errors usually mean clutch slip, which worsens quickly.
Symptoms
- Slipping when pulling away
- Flaring engine speed between gears
- Harsh or delayed engagement
Likely causes, most common first
- Low or burnt transmission fluid
- First gear clutch pack worn
- Shift solenoid stuck
- Valve body wear leaking pressure
Read P0731 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0731 means the ratio between input and output shaft speed in first gear does not match what first gear should produce. The transmission is being told to hold first and is not holding it - in plain terms, something is slipping.
First gear carries the highest torque of any ratio, so it is where marginal clutch or pressure problems show up first. Fluid level and condition come before anything else: low fluid or fluid that smells burnt explains a great many of these codes, and refusing that check has turned many recoverable transmissions into rebuilds.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0731
“Transmission P0731 code. Vehicle will not shift into 1st gear when idle but will stay in 3 or 4 gear. Speedometer would indicate high speed when pressing on accelerator. At traffic light when light turn green car rev but would not shift into gear. Has only 130K miles. Car was towed to dealer and required a new transmission.”2016 Hyundai Elantra · Jun 2026
“I am the second owner of the vehicle and there were no disclosed repairs or issues provided at the time of purchased. The 2012 Ford F-150, is shifting sporadically and harsh. Throwing out code P0722. Which directly relates to the below previous recall. Recall Reference Number: 24S37. Issue: An intermittent failure of the output shaft speed (OSS) sensor in the transmission can lead to an unintended downshift to first gear. Affected Vehicles: Some 2014 Ford F-150 models. Reason for Recall: The abrupt downshift can cause a loss of vehicle control, increasing the risk of a crash. Potential Codes: P0720, P0722, P0731 and/or P1500”2012 Ford F-150 · Feb 2025
“Sudden loss of forward gears. Failure happened on highway at highway speeds. Had to carefully maneuver the truck off the road. Failure in both towing and unloaded operation. Truck will not shift in or out of drive (1-4) but reverse is still functional. Diagnostic trouble code P0731-00 and P0734 "Gear 1 and 4 Shift Incorrect Ratio". Both the dealer and RAM confirm this transmission failure. RAM has realeased a TSB which covers this failure but hasn't released a recall.”2022 Ram 3500 · Apr 2024
Show 7 more owner reports
“Truck has 6500 miles, went to put it in reverse from drive in busy intersection and transmission started to slip. Truck ultimately wouldn't drive at all. Started throwing codes (P0731-00 in particular) and found out that it needs a new K1 clutch snap ring repair. There are more than 300 people with this issue, this has not only happened with me from my research on forums about this code being thrown. This is a 2022 with 6500 miles, there are too low of miles on this truck for it to be having a problem like this!”2022 Ram 5500 · Dec 2023
“I am a commercial driver for Hibbs Haulers and was driving the 2022 Ram 3500 DRW 4X4 company truck. Production month was September 2022. After driving at a slow speed in heavy traffic the truck felt like it fell out of drive and into neutral. I was able to move slowly but transmission temp started to climb into 220 plus degrees and a temperature warning came on for the transmission so I pulled onto the shoulder. I was able to use reverse but I did not have gears 1 through 4. A MIL code P0731 came on during this incident.”2022 Ram 3500 · Sep 2023
“The contact owns a 2022 Ram 3500. The contact stated while depressing the accelerator pedal, the vehicle made an abnormal sound. Additionally, the vehicle occasionally would not start as needed. The fault code: P0731 (Gear 1 Incorrect Ratio) was retrieved. The vehicle was towed to a dealer, where it was diagnosed with transmission failure. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was 26,000.”2022 Ram 3500 · Jan 2023 · 26,000 mi
“The contact owns a 2013 Ford F-150. The contact stated that after starting the vehicle, the transmission failed to shift into first gear. The transmission warning light was illuminated. The "Return to Park" message was displayed. The contact diagnosed and retrieved DTC Code: P0731 (Gear 1 Incorrect Ratio). The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was made aware of the failure but informed the contact that Customer Satisfaction Program: 19N01 (Transmission Molded Leadframe Extended Coverage) had expired. The failure mileage was approximately 196,000.”2013 Ford F-150 · Sep 2022 · 196,000 mi
“Transmission is giving out has turned off while driving and sometimes it won't go reverse and Or won't go into gears Machine shows code p0731”2017 Ford Explorer · Jul 2022
“The truck has abruptly shifted into first gear multiple times while driving at highway speeds or speeds far above what first gear should be allowed, failed to shift out of first gear multiple times at stop lights, and has failed to accelerate into first gear from park also throwing a P0731 code and warning indicator light.”2011 Ford F-150 · Jun 2022
“on several occasions while driving at 50+ mph my truck suddenly downshifts from 6th gear to 1st gear causing the rear wheels to lock up and skid. i have taken the vehicle to the dealership and they refuse to do anything because they can not duplicate the issue. this has happened several times the last time was on the freeway causing me to shoot over 2 lanes of traffic almost causing an accident. the ford dealership and the extended warranty company ameriplus both refuse to help because they both say that they can not duplicate the problem but the vehicle comes up with dtc codes p0731 and p0722”2014 Ford F-150 · May 2021
Cars that report P0731 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0731?
Drive gently to a shop - ratio errors usually mean clutch slip, which worsens quickly.
How much does it cost to fix P0731?
Typical US repair costs range from $200 for the simplest fix (fluid and filter service) to $5,000 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P0731. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.