Understanding and Fixing P0733: Gear 2 Incorrect Ratio

If you’re experiencing issues with your car’s automatic transmission, one problem that you may encounter is the P0733 error code. This error code indicates that there is an incorrect ratio in the second gear of the transmission. Understanding the causes and finding solutions for this problem can help you get your car back on the road smoothly. In this article, we will delve into the details of the P0733 error code, explore its causes, and provide step-by-step instructions to fix it.

1. Introduction to P0733 Error Code

The P0733 error code is a diagnostic trouble code that is specific to automatic transmissions. It is generated when the Engine Control Unit (ECU) detects an improper gear ratio in the second gear. This means that the transmission is not shifting properly between gears, which can lead to issues such as harsh shifting, poor acceleration, and decreased fuel efficiency.

2. Understanding Gear Ratios in Automatic Transmissions

Before we dive into the causes of the P0733 error code, it’s essential to have a basic understanding of gear ratios in automatic transmissions. Gear ratios determine the relationship between the engine’s speed (RPM) and the speed of the vehicle’s wheels. Each gear has a specific ratio, allowing the transmission to provide the necessary torque and speed for various driving conditions.

3. Causes of P0733 Error Code

Several factors can contribute to the occurrence of the P0733 error code. Let’s explore some of the common causes:

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a) Worn or Damaged Transmission Components

Over time, the internal components of the transmission can wear out or become damaged. This can lead to improper gear engagement and result in the P0733 error code. Components such as clutch packs, bands, or the valve body may need to be replaced to resolve the issue.

b) Low Transmission Fluid Level

Insufficient transmission fluid can also trigger the P0733 error code. Low fluid levels can cause inadequate hydraulic pressure, leading to improper gear shifts. Regularly checking and maintaining the correct transmission fluid level is crucial to prevent this problem.

c) Faulty Transmission Control Module

The Transmission Control Module (TCM) is responsible for managing the operation of the transmission. A faulty or malfunctioning TCM can result in incorrect gear ratios and trigger the P0733 error code. In such cases, the TCM may need to be repaired or replaced.

4. Diagnosing P0733 Error Code

To effectively address the P0733 error code, it’s important to diagnose the underlying issue accurately. Here are some steps to help you diagnose the problem:

a) Using a Diagnostic Scanner

Start by connecting a diagnostic scanner to your car’s OBD-II port. The scanner will retrieve the error code and provide additional information about the problem. This will help you determine if the issue is specific to the second gear or if there are other related error codes.

b) Checking Transmission Fluid Level and Condition

Next, check the transmission fluid level and condition. Refer to your vehicle’s manual for the correct procedure to follow. If the fluid level is low, top it up with the manufacturer-recommended fluid. Ensure that the fluid is clean and doesn’t have a burnt smell, as this may indicate internal transmission problems.

c) Inspecting Transmission Components

Inspect the transmission components for any signs of wear or damage. This may require removing the transmission pan to access the internal parts. Look for worn clutch packs, damaged bands, or any other visible issues. If you’re not confident in performing this inspection, it’s recommended to consult a professional mechanic.

5. Fixing P0733 Error Code

Once you have diagnosed the underlying cause of the P0733 error code, it’s time to fix the problem. Here are the steps to follow:

Step 1: Check and Top Up Transmission Fluid

If the transmission fluid level is low, add the appropriate fluid recommended by the manufacturer. Be cautious not to overfill the transmission, as it can lead to other issues. Ensure the fluid is at the correct level before proceeding to the next step.

Step 2: Inspect and Replace Damaged Transmission Components

If you have identified worn or damaged transmission components, it’s crucial to replace them. Consult your vehicle’s service manual or seek professional assistance for the correct replacement procedure. Replace the faulty components and ensure proper installation.

Step 3: Resetting the Transmission Control Module

If the P0733 error code was triggered by a faulty Transmission Control Module (TCM), resetting the module may resolve the issue. Disconnect the car battery for a few minutes to clear the TCM’s memory. Reconnect the battery and start the car. The TCM will relearn the driving patterns, and this may help eliminate the error code.

6. Tips for Preventing P0733 Error Code

Prevention is always better than cure. To minimize the chances of encountering the P0733 error code, consider the following tips:

  • Regularly check and maintain the proper transmission fluid level.
  • Follow the manufacturer’s recommended service intervals for transmission fluid and filter changes.
  • Drive smoothly and avoid harsh acceleration or abrupt gear changes.
  • If you notice any unusual symptoms in your transmission, such as slipping or delayed shifting, have it inspected by a professional mechanic promptly.


The P0733 error code can be a frustrating problem for car owners. However, by understanding the causes and following the step-by-step solutions provided in this article, you can effectively diagnose and fix the issue. Remember to perform regular maintenance and address any transmission problems promptly to ensure smooth and reliable operation of your vehicle’s automatic transmission.


Q1: Can I continue driving my car with the P0733 error code?

A1: It’s not recommended to continue driving your car with the P0733 error code. The incorrect gear ratio can cause further damage to the transmission if left unresolved. Have your vehicle inspected by a professional mechanic to determine the exact cause and take appropriate action.

Q2: How much will it cost to fix the P0733 error code?

A2: The cost of fixing the P0733 error code can vary depending on the underlying cause and the labor rates in your area. Simple fixes such as topping up the transmission fluid may be relatively inexpensive, while replacing worn transmission components or a faulty TCM can be more costly. It’s best to consult a professional mechanic for an accurate assessment and cost estimate.

Q3: Can I fix the P0733 error code myself, or should I take it to a mechanic?

A3: The complexity of fixing the P0733 error code depends on the underlying cause and your mechanical skills. Simple tasks like checking and topping up the transmission fluid can be done by most car owners. However, diagnosing and replacing internal transmission components or dealing with a faulty TCM may require specialized tools and expertise. If you’re unsure or uncomfortable with performing these tasks, it’s recommended to seek professional assistance.