How to Fix Code P0730: Guide to Solving Transmission Problems

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man working on car transmission

If you're experiencing transmission problems, the code P0730 is probably what your OBD diagnostic tool will show. The cause of the P0730 code can be confusing, especially when it's associated with various symptoms. However, we are here to help! So, if you're having trouble diagnosing and fixing this problem, read on! 

This blog post will discuss what the P0730 code means and tips on fixing it. We will also look closer at some of the common causes and symptoms of this code. So if you're experiencing transmission problems, stay tuned!

What is Code P0730?

P0730 is the OBD-II generic code that indicates an incorrect gear ratio detected in an automatic transmission. When driving, a ratio of engine speed and throttle position is applied to the speed of the gearbox to determine what gear it will engage. 

Once the sensor data detects a problem with any gear within the transmission, the P0730 code appears. This code is also often associated with the P0729, P0731, P0732, P0733, P0734, P0735, and P0736 trouble codes.

Symptoms of Code P0730

The first sign you'll notice is that the Check Engine Light illuminates on the dashboard. Aside from that, you may also experience the following signs:

  • Slipping within the transmission
  • Poor overall transmission performance 
  • Transmission stuck in a low gear for too long
  • Transmission stays in one gear for an extended period

Causes of Code P0730

Since the Code P0730 is a generic trouble code, P0730 doesn't pinpoint the exact cause of any gear ratio failure making it hard to find the exact issue causing this trouble. However, the possible causes incorporated with this fault code are:

  • Low transmission fluid
  • Dirty transmission fluid
  • Damaged transmission components
  • Clogged fluid lines due to blockage
  • Faulty transmission control module
  • Torque converter clutch issue
  • Problem with the shift solenoids

How to Diagnose Error Code P0730?

Before fixing the issue, you'll need to diagnose it. There are several tests you can perform to help pinpoint the cause of the problem. Here are some of the more common tests:

Step-by-Step Guide

  1. First, you will need an OBD2 scanner. Once you have that, clear the code and take a test drive. If the light returns, you'll know it's an issue with your transmission.
  2. From there, check the fluid level to ensure its at the correct level and is not burnt or contaminated. You should also inspect the transmission filter for any debris or blockages. If everything looks good, then move on to a deeper examination of the transmission.
  3. Test the vehicle's transmission fluid for abnormalities. If the fluid is discolored, thick, or smells burnt, then there's a good chance you have a transmission issue.
  4. Check the transmission solenoid for any physical damage and test its electrical resistance.
  5. Once you've checked all of these components, you can start resolving the issue. In most cases, the p0730 code is caused by a sensor or solenoid failure. If that's the case, replacing the component will fix the issue.

How to Fix Code P0730?

After thoroughly diagnosing your car and finding out that the cause is a sensor or solenoid failure, bring your car to a repair shop for sensor and solenoid replacement. However, if you have a tight budget, you can try replacing the component yourself. The following steps will walk you through transmission solenoid replacement.

Step-by-Step Guide

  1. Park your car on a level surface.
  2. Open the hood and make sure to disconnect the battery cables.
  3. Remove the air cleaner assembly.
  4. Locate the transmission solenoid and remove the electrical connector.
  5. Unbolt the solenoid from the transmission and replace it with a new part.
  6. Reconnect the electrical connector and reattach the air cleaner assembly.
  7. Reconnect the battery cables and start your car.

If all else fails, it is most likely that the sensor needs to be replaced. You might need to bring your car to a repair shop for diagnosis and repair this time. Aside from replacing the solenoid and sensor, several ways may fix the Code P0730 issue, including:

  • Check all the electrical connections and wires connecting sensors to the transmission control module.
  • Repair or replace any damaged wires in and around the transmission control module.
  • Repair or replace any broken wires in and around the transmission speed sensor.

Common Mistakes When Diagnosing the P0730 Code

When diagnosing the P0730 trouble code, the most common mistake is replacing the wrong part or not replacing the part at all. It is crucial to diagnose the issue before attempting any repairs.

Another common mistake is not clearing the trouble code after making repairs. Make sure you clear the code after completing any repairs to track whether or not the repair was successful accurately.

Code P0730 FAQs

1. Is the P0730 Code Serious?

The P0730 code is not a serious issue, but it can cause problems with the transmission. It is vital to fix this code as soon as possible to avoid further damage. 

Failure to solve the P0730 code can cause transmission speed abnormalities, decreased fuel economy, transmission slippage, and premature transmission failure. So, when the P0730 code appears, it is best to have it diagnosed by a professional mechanic. 

2. Can I drive with the code P0730

Yes, you can drive with the code P0730 as long as it doesn't cause problems with the transmission. But it would be best to get the code fixed as soon as possible to avoid worsening the issue.

3. Can I fix the 2nd gear incorrect ratios myself?

No, you cannot fix the gear ratio yourself. It is a complex issue that requires special tools and knowledge. You will need to take it to a qualified technician to inspect and repair it.

4. How about the 4th gear incorrect ratio? Can I fix it myself?

Like the 2nd gear ratio, the fourth gear incorrect ratio is also a complex issue requiring special tools and knowledge. You should also send your car to a qualified mechanic.

5. Is the OBD2 scanner necessary when diagnosing this trouble code?

Yes, the OBD scan tool is crucial in diagnosing trouble codes. It is helpful to detect the issue before bringing your car to a repair shop. As a result, you may resolve the problem without costing you a dime!


In conclusion, if you experience any of the symptoms or signs listed above, you can try to fix it yourself if you have professional knowledge about these specific repairs. However, if you aren't sure about your skills, it is best to take your car to a qualified technician and inspect and repair the transmission. 

Always remember that the sooner you address the issue, the better, as it can cause further damage to the transmission. Have questions? Feel free to leave a comment below!