P0735 – Gear 5 Incorrect Ratio

The P0735 error code, also known as “Gear 5 Incorrect Ratio,” is a transmission issue that occurs when the transmission control module (TCM) detects a problem with shifting into or out of fifth gear. This error can be caused by various factors, including internal transmission failure, malfunctioning PCM or TCM, faulty transmission valve body, wiring issues, low or contaminated transmission fluid, or shift solenoid failure.

Key Takeaways:

• The P0735 error code indicates a problem with the transmission’s ability to shift into fifth gear correctly.
• Common symptoms of P0735 include an illuminated check engine light, poor fuel economy, and difficulty shifting.
• Proper diagnosis and repair of P0735 require the expertise of a certified mechanic.
• Causes of the P0735 code can range from internal transmission failure to wiring issues.
• It is crucial to address the underlying causes of the P0735 code to prevent further transmission damage.

What Does the P0735 Code Mean?

The P0735 code, also known as “Gear 5 Incorrect Ratio,” is a transmission error code that indicates a problem with the transmission’s ability to enter the fifth gear correctly. This code is triggered when the rotational speed of the input speed sensor and the transmission output speed sensor do not match what is expected in fifth gear.

The transmission control module (TCM) plays a crucial role in controlling the transmission. It uses solenoids to manipulate the fluid pressure that engages the different gears. When the TCM detects an incorrect gear ratio in the fifth gear, it logs the P0735 code.

This image showcases the intricate gear system of a transmission, highlighting the complex mechanism responsible for shifting between gears.

Using a scan tool plugged into the vehicle’s OBD-II port allows mechanics to retrieve the trouble codes stored in the TCM. By diagnosing the P0735 code, mechanics can accurately identify the issue and proceed with the appropriate repairs. It is crucial to take the vehicle to a qualified repair shop and consult a certified mechanic for diagnosis and repairs related to the P0735 code.

Common Causes of the P0735 Code

The P0735 code can be triggered by various factors that affect the proper functioning of the transmission. Identifying and addressing these underlying causes is essential to resolving the P0735 code. Common causes of the P0735 code include:

1. Internal Transmission Failure: Problems within the transmission system, such as worn gears or a damaged clutch, can lead to the incorrect gear ratio.
2. Malfunctioning PCM or TCM: The Powertrain Control Module (PCM) or Transmission Control Module (TCM) may malfunction, affecting the transmission’s ability to shift into the correct gear.
3. Faulty Transmission Valve Body: Issues with the transmission valve body, which controls the flow of transmission fluid, can result in incorrect gear ratios.
4. Wiring Issues: Poor electrical connections or damaged wiring can disrupt signals between the transmission components, causing gear ratio problems.
5. Low or Contaminated Transmission Fluid: Insufficient or contaminated transmission fluid can affect the hydraulic pressure necessary for proper gear shifting.
6. Shift Solenoid Failure: Malfunctioning shift solenoids, responsible for directing the flow of transmission fluid to engage specific gears, can lead to incorrect gear ratios.

It is important to conduct a thorough diagnosis to determine the exact cause of the P0735 code before proceeding with repairs. A table summarizing the common causes of the P0735 code is provided below:

Diagnosing and repairing the specific cause of the P0735 code is best left to certified mechanics, who have the expertise and required tools to resolve transmission-related issues effectively.

Common Symptoms of the P0735 Code

When encountering the P0735 code, several common symptoms may manifest in your vehicle. These indicators serve as warning signs that your transmission is not functioning optimally, particularly in relation to entering or shifting into fifth gear. It is crucial to recognize these symptoms as they can help in identifying and resolving the issue at hand.

1. Illuminated Check Engine Light

One noticeable symptom of the P0735 code is the illumination of the check engine light on your dashboard. The check engine light serves as a general warning sign for various malfunctions in your vehicle’s systems. When it appears alongside the P0735 error code, it is a strong indication of a transmission-related issue that requires attention.

2. Poor Fuel Economy

Another symptom associated with the P0735 code is poor fuel economy. If you notice a sudden increase in fuel consumption without any apparent reason, it may be attributed to the transmission’s inability to shift into the correct gear. This inefficiency can result in decreased fuel efficiency, leading to more frequent trips to the gas station.

3. Inability to Shift Properly

The inability to shift properly is a key symptom that highlights the transmission’s struggle to engage fifth gear. You may experience difficulty shifting into or out of fifth gear, or notice irregular shifting patterns while driving. This can lead to a loss of power, reduced acceleration, and a less enjoyable driving experience overall.

If you encounter any of these common symptoms associated with the P0735 code, it is highly recommended to have your vehicle diagnosed by a certified mechanic. Addressing the underlying transmission issue promptly can prevent further damage and potential safety hazards.

How to Diagnose the P0735 Code

Proper diagnosis of the P0735 code requires thorough troubleshooting and may require specialized tools and knowledge. When faced with this error code, it is highly recommended to consult a certified mechanic or technician who has expertise in transmission diagnosis. They have the skills and experience to accurately identify the underlying cause of the P0735 code and recommend appropriate repairs.

One of the essential tools used in diagnosing the P0735 code is a scan tool. This device connects to the vehicle’s OBD-II port and retrieves the trouble codes stored in the system. By accessing the code associated with the P0735 error, the mechanic gains valuable information about the specific issue affecting the transmission.

With the scan tool providing initial insight, the mechanic will then proceed with various diagnostic procedures to understand the root cause. These procedures may include:

1. Performing a visual inspection of the transmission components to check for any visible damage or obvious signs of failure.
2. Checking the transmission fluid level and condition. Low or contaminated fluid can contribute to gear ratio problems.
3. Verifying the electrical connections and wiring related to the transmission system. Faulty or loose connections can disrupt signal transmission and impact gear shifting.
4. Conducting functional tests on various transmission components, such as shift solenoids and pressure sensors, using specialized equipment.
5. Reviewing live data from the transmission control module (TCM) to analyze input and output speed sensor readings, fluid pressure, and other relevant parameters.

Through these diagnostic steps, the mechanic can pinpoint the specific issue causing the incorrect ratio in gear 5 and provide an accurate diagnosis for efficient repair.

How to Fix the P0735 Code

Once the underlying cause of the P0735 code has been identified, it is important to take appropriate steps to fix the issue. The specific repairs required may vary depending on the diagnosis, but here are some common solutions:

1. Transmission Repair

If the P0735 code is caused by internal transmission failure, the transmission may need to be repaired or replaced. A certified mechanic will be able to assess the extent of the damage and recommend the best course of action.

2. PCM and TCM Repair

In some cases, the P0735 code may be triggered by a malfunctioning Powertrain Control Module (PCM) or Transmission Control Module (TCM). Repairing or replacing these components may resolve the issue and prevent further transmission problems.

3. Transmission Valve Body Replacement

Faulty transmission valve bodies can also cause gear ratio issues. Replacing the transmission valve body can result in smoother shifting and improved overall performance.

4. Wiring Repair

Wiring issues, such as damaged or loose connections, can disrupt the transmission’s communication with the TCM. Repairing any wiring problems can restore the proper functioning of the transmission.

5. Transmission Fluid Change

Low or contaminated transmission fluid can affect the performance of the transmission. A transmission fluid change, along with a thorough inspection for leaks and other issues, can help address the P0735 code.

6. Shift Solenoid Replacement

Faulty shift solenoids can prevent the transmission from shifting properly. Replacing these solenoids can resolve gear ratio problems and improve the transmission’s overall performance.

It is important to note that these are general repair options, and the actual repairs required may vary depending on the specific make and model of the vehicle. Consulting a certified mechanic is highly recommended to ensure accurate diagnosis and proper repair procedures.

Other Notes About P0735

While the P0735 code is a significant transmission-related error code, it is crucial to consider other transmission error codes as well before troubleshooting specifically for P0735. The proper operation of the transmission is essential for ensuring optimal vehicle performance and drivability. It is advisable to consult the vehicle-specific repair manuals for detailed information and guidance on diagnosing and repairing transmission error codes.

If you are unsure or lack the necessary expertise, it is always best to seek assistance from a professional mechanic. They can provide the expertise needed to accurately diagnose and resolve transmission issues. Avoid attempting repairs without proper knowledge or understanding, as this may lead to further complications.

Other Transmission Error Codes

• P0700 – Transmission Control System Malfunction
• P0715 – Input/Turbine Speed Sensor Circuit Malfunction
• P0720 – Output Speed Sensor Circuit Malfunction
• P0730 – Incorrect Gear Ratio

Inaccurate gear ratios and other transmission-related error codes can significantly impact the overall performance of a vehicle. It is vital to address these issues promptly to prevent further damage and ensure safe driving.

OBD-II Codes

The P0735 code and other transmission error codes fall under the broader category of OBD-II (On-Board Diagnostic) codes. These codes provide valuable information about various vehicle systems, including the transmission. Utilizing an OBD-II scanner can help retrieve and interpret these codes, assisting mechanics in diagnosing and resolving issues effectively.

Proper understanding and interpretation of OBD-II codes are crucial for accurate diagnosis and repair. It is recommended to rely on professional knowledge and expertise when dealing with complex transmission issues.

Conclusion

In conclusion, the P0735 code, which signifies “Gear 5 Incorrect Ratio,” is a significant transmission issue that should not be ignored. If you experience symptoms such as an illuminated check engine light, poor fuel economy, or difficulties with shifting, it is crucial to address the problem promptly.

There are several potential causes for the P0735 code, including internal transmission failure, malfunctioning PCM or TCM, faulty transmission valve body, wiring problems, low or contaminated transmission fluid, and shift solenoid failure. To accurately diagnose and repair this error code, it is highly recommended to seek assistance from a certified mechanic with expertise in transmission issues.

In some cases, resolving the P0735 code may require professional assistance, especially if further analysis and resolution through ECU file analysis are necessary. It is essential to understand the importance of proper diagnosis and repair to ensure the optimal performance and drivability of your vehicle.