Understanding and Fixing P0736 – Gear 5 Incorrect Ratio

As a car enthusiast and DIY expert, I understand how frustrating it can be when your vehicle encounters problems.

One common issue that many people face is the error code P0736 – Gear 5 Incorrect Ratio. In this article, we will dive deep into understanding this error code and provide you with step-by-step instructions on how to fix it. So, let’s get started!

Understanding P0736 – Gear 5 Incorrect Ratio

When your car’s onboard diagnostic system detects a problem with the gear ratio in the fifth gear, it triggers the error code P0736. This error code indicates that there is a mismatch between the RPM (revolutions per minute) and the speed of the vehicle in fifth gear. Several factors can contribute to this issue, including a faulty transmission solenoid, damaged wiring, or even a malfunctioning transmission control module (TCM).

Causes of P0736

There are several potential causes for the P0736 error code. Some common culprits include:

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  1. Faulty Transmission Solenoid: The transmission solenoid is responsible for regulating the flow of transmission fluid. If it becomes faulty or clogged, it can lead to incorrect gear ratios.
  2. Damaged Wiring: Loose or damaged wiring connections can interfere with the signals sent to the transmission system, resulting in gear ratio discrepancies.
  3. Malfunctioning Transmission Control Module (TCM): The TCM is the brain of the transmission system, controlling gear shifts based on various inputs. A malfunctioning TCM can cause incorrect gear ratios.
  4. Transmission Issues: In some cases, the error code may indicate underlying transmission problems, such as worn-out gears or clutch issues.

Diagnosing P0736

Before proceeding with any repairs, it’s crucial to diagnose the exact cause of the P0736 error code. Here are the steps to follow:

  1. Using a Diagnostic Scanner: Connect a diagnostic scanner to your vehicle’s OBD-II port and retrieve the error codes. This will help you pinpoint the specific issue causing the gear ratio problem.
  2. Checking Transmission Fluid Level and Condition: Inspect the transmission fluid level and quality. Low fluid levels or contaminated fluid can affect the gear shifting and lead to error codes. If necessary, top up the fluid or perform a complete fluid flush.
  3. Inspecting the Transmission System: Visually inspect the transmission system for any visible signs of damage, such as leaks or loose connections. Pay close attention to the wiring harness and connectors related to the transmission.

Fixing P0736

Once you have identified the root cause of the P0736 error code, you can proceed with the necessary repairs. Here is a step-by-step guide to fixing the issue:

Step 1: Check for Loose or Damaged Wiring

Inspect all the wiring connections related to the transmission system. Look for any loose or damaged wires, frayed insulation, or corroded connectors. If you find any issues, repair or replace the affected wiring as needed.

Step 2: Inspect and Replace the Transmission Solenoids

Remove the transmission pan and locate the transmission solenoids. Inspect them for any signs of damage or debris. If a solenoid is found to be faulty, replace it with a new one. It’s also a good idea to clean the solenoid valves and the transmission valve body during this process.

Step 3: Check and Replace the Transmission Control Module (TCM)

If the previous steps didn’t resolve the issue, the TCM might be at fault. Consult your vehicle’s service manual or seek professional help to properly diagnose and replace the TCM if necessary.

Step 4: Repair or Replace the Transmission Itself

If none of the previous steps have resolved the P0736 error code, it may indicate a more severe transmission problem. In such cases, it is recommended to take your vehicle to a qualified mechanic or transmission specialist for further diagnosis and repair.

Tips to Prevent P0736

Prevention is always better than cure. Here are some tips to help you prevent the occurrence of the P0736 error code:

  • Regular Maintenance and Fluid Checks: Follow the manufacturer’s recommended maintenance schedule and ensure that the transmission fluid is regularly checked and changed as needed.
  • Driving Habits and Care for the Transmission: Avoid aggressive driving, sudden shifts, and excessive towing, as these factors can put unnecessary stress on the transmission and lead to gear ratio issues.


Dealing with the P0736 error code can be daunting, but with the right knowledge and approach, you can address the issue effectively. Remember to diagnose the problem accurately, follow the step-by-step instructions provided, and consider seeking professional assistance if needed. By taking proper care of your vehicle’s transmission and following preventive measures, you can minimize the chances of encountering the P0736 error code in the future.


Can I continue driving my car with the P0736 error code?

  1. It is not recommended to drive your car with the P0736 error code, as it indicates a problem with the gear ratio in the fifth gear. Continuing to drive in this condition can potentially cause further damage to the transmission.

Can I fix the P0736 error code myself, or should I seek professional help?

  1. Depending on your level of expertise and access to tools, you may be able to fix the P0736 error code yourself. However, if you are unsure or uncomfortable with the repair process, it is advisable to seek professional help from a qualified mechanic or a transmission specialist.

Are there any preventive measures to avoid the P0736 error code?

  1. Yes, there are preventive measures you can take to reduce the chances of encountering the P0736 error code. Regular maintenance, including checking and changing the transmission fluid as recommended, and adopting good driving habits, can help prevent gear ratio issues.