What Codes Will This Page Cover?
This page will cover the following diagnostic trouble codes:
- P0731 Gear 1 Incorrect Ratio
- P0732 Gear 2 Incorrect Ratio
- P0733 Gear 3 Incorrect Ratio
- P0734 Gear 4 Incorrect Ratio
- P0735 Gear 5 Incorrect Ratio
These generic trouble codes are all related, and they will require similar approaches for fixing the engine issue.
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What Is the P0731 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
The P0731, P0732, P0733, P0734, and P0735 engine diagnostic trouble codes all indicate that the Powertrain Control Module (PCM) or Engine Control Module (ECM) has detected that the specified gear has a gear ratio that is in some way different from the default standard for that vehicle. Your vehicle’s PCM might use your transmission speed sensor to determine the gear ratio and torque converter slip, allowing it to understand when there’s a problem. The labeling of the code indicates which gear is impacted—1st gear is the gear the vehicle is in when it’s going the slowest, while 5th gear is the fastest gear.
You may also be interested in P0730 Incorrect Gear Ratio
More About Error Code P0731
When the P0731, P0732, P0733, P0734, or P0735 codes are set in your PCM, it indicates that there is some kind of RPM difference between the Input RPM Sensor and the Transmission Output RPM Sensor. In modern vehicles with an automatic transmission engine type, these transmission sensors must run at all times to ensure the automatic transmission functions properly. An issue between the two can indicate that the transmission is slipping or some other issue within the automatic transmission process.
What Are the Symptoms of a P0731 Code?
The common symptoms of the P0731, P0732, P0733, P0734, and P0735 codes vary tremendously. In some cases, the codes may be barely noticeable, while in others, they can cause the transmission to malfunction significantly and create serious problems for the driver. You may see that the vehicle shifts improperly, sometimes refusing to shift at all, and in other cases, the gear shift may slip. You will also notice a decrease in fuel economy. However, even if there are no adverse conditions, you will likely see the check engine light or malfunction indicator lamp turn on.
What Are Some Causes of a P0731 Code?
There are many different reasons you might see the P0731, P0732, P0733, P0734, and P0735 codes. The gear shift solenoid for the gear in question may be defective. A faulty solenoid is a mechanical issue that can result in transmission problems over time. Issues with the forward clutch or valve body can also cause these issues. One of the more common problems is issues with your vehicle’s transmission fluid. If you have low transmission fluid levels or dirty transmission fluid, the hydraulic passages may be restricted, causing the transmission not to work as intended. In rare cases, it may be due to a bad battery or even a PCM malfunction, but these are uncommon.
How Serious Is the P0731 Code?
The P0731, P0732, P0733, P0734, and P0735 codes should be considered seriously because they relate to your vehicle’s transmission. In general, assume that issues with the transmission are very serious and should be treated early. This is especially important if you notice gear shifting issues, but even if there are no problems that you can notice, you should still fix the problem. Unfixed transmission problems can easily lead to serious transmission concerns that can be much more difficult and expensive to solve.
Can I Still Drive with a P0731 Code?
If the P0731, P0732, P0733, P0734, or P0735 codes are active on your vehicle, you should avoid driving if possible. Again, transmission codes are commonly very serious, so when you know you’re experiencing an issue with the transmission, it’s best not to take any chances. You can contact your repair expert to get more information about whether it will be safe to drive your vehicle in for an inspection or whether you should get a tow truck instead.
How Easy Is It to Diagnose a P0731 Code?
You might accidentally look for several potential misdiagnoses when it comes to P0731, P0732, P0733, P0734, and P0735 codes. These misdiagnoses may include general engine misfiring problems, issues with your vehicle’s internal transmission, or problems with your driveline. The diagnostic process can be difficult, so most people recommend getting expert assistance with these codes. Sometimes it’s as easy as cleaning the dirty fluid, but sometimes it’s fixing an electrical issue or finding a leak to improve fluid pressure. Repair steps will vary depending on the underlying cause and your specific vehicle. If your scan tool indicates one of these codes, it’s a good idea to talk to an expert instead of potentially making a common mistake in your diagnosis.
How Difficult Is It to Inspect a P0731 Code?
Inspection can be just as difficult as diagnosis, especially since the inspection often requires you to record the freeze frame information and duplicate code setting conditions. These are diagnostics that can be much easier for an expert to do than you, especially because it requires very specific diagnostic tools that most DIYers don’t have. When it comes to a problem this serious, an experienced mechanic’s assistance will likely be the most helpful. They’ll have a manual for vehicle problems, experience with various vehicle models, and diagnostics knowledge.
Need Additional Help with Your P0731 Code?
Most people need extra help with the P0731, P0732, P0733, P0734, and P0735 codes. These are not simple codes to diagnose or inspect, and it’s much better for most people to get help from an expert with the training and knowledge necessary to figure out what’s wrong and fix it.
The good news is that it’s easy to find a repair shop in your area with certified mechanics who can help you fix the problem. A local auto repair shop is a great way to get common repairs, including for issues with the P0731, P0732, P0733, P0734, and P0735 codes.
When you do an OBD scan, you may also find other codes, especially if an underlying transmission cause exists. The OBD-II database from KBB.com can help you understand what these other codes mean for your vehicle.
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