Imagine you’re driving down the highway, enjoying a smooth ride, when suddenly your car starts to jerk and shudder. You pull over, check your engine, and see a warning light on your dashboard. Your heart sinks as you realize it’s the dreaded “Check Engine” light, and the code it throws is P0720. You’re left wondering what it means and how to fix it.
What Does P0720 Code Mean?
The P0720 code, also known as the “Output Speed Sensor Circuit Malfunction” or “Transmission Output Speed Sensor Circuit Malfunction”, is a diagnostic trouble code (DTC) that relates to your car’s transmission. The code indicates a problem with the output speed sensor (OSS) circuit, which plays a crucial role in monitoring the speed of your car’s transmission output shaft.
Understanding the Output Speed Sensor
The output speed sensor (OSS) is a critical component of your car’s transmission. It’s a small, magnetic sensor that sits near the transmission’s output shaft. This sensor measures the speed of the output shaft, which is the shaft that connects the transmission to the driveshaft.
Why the Output Speed Sensor Matters
The OSS is crucial for several reasons:
- Accurate Transmission Control: The transmission control module (TCM) uses the OSS signal to determine the correct gear ratio and shifting points.
- Smooth Gear Shifting: The information from the OSS is used to optimize gear changes for a seamless and smooth driving experience.
- Fuel Economy: The TCM uses the OSS data to adjust fuel consumption and optimize engine performance.
- Preventing Damage: If the OSS fails, the TCM may not be able to shift gears correctly, potentially leading to transmission damage.
Common Causes of P0720 Code
Several factors can cause the P0720 code, including:
- Defective Output Speed Sensor: The most common reason for this code is a faulty OSS. Over time, these sensors can wear out, become damaged, or get clogged with debris.
- Wiring Issues: Damaged wiring or loose connections in the OSS circuit can also trigger the P0720 code.
- Transmission Control Module Problems: A faulty TCM can sometimes misinterpret the OSS signal, leading to the P0720 code.
- Transmission Fluid Issues: Low transmission fluid levels or contaminated fluid can impact the OSS and trigger this code.
- Foreign Object Damage: Debris or foreign objects can sometimes interfere with the OSS, affecting its operation.
Diagnosing and Fixing the P0720 Code
Diagnosing and fixing the P0720 code requires a methodical approach. Here’s what you need to do:
- Use a Diagnostic Scanner: The first step is to use an OBD II scanner, such as a Dealer Scanner for European Cars, to retrieve the P0720 code and any associated data. This scanner will provide valuable information about the specific problem.
- Check the OSS: Once you have the code, inspect the OSS for any signs of damage, wear, or debris. If the sensor appears damaged, it needs to be replaced.
- Inspect Wiring: Carefully examine the wiring and connectors in the OSS circuit for any breaks, shorts, or loose connections. Repair or replace any damaged wiring.
- Check Transmission Fluid: Ensure that the transmission fluid level is correct and that the fluid is clean and free of contaminants.
- Inspect the TCM: If the OSS and wiring appear fine, there could be a problem with the TCM. This can be more challenging to diagnose and may require professional assistance.
- Clear the Code: Once you’ve addressed the potential issues, clear the P0720 code using the OBD II scanner and test drive your car. If the code returns, it’s likely that the problem wasn’t resolved, and further investigation is needed.
Before checking the OSS, it is helpful to visually inspect the output shaft for any signs of damage or debris.
Frequently Asked Questions About the P0720 Code
Q: Can I drive my car with a P0720 code?
A: While it might be tempting to ignore the P0720 code and continue driving, it’s not advisable. Ignoring this code can lead to further transmission damage and could affect your car’s performance.
Q: Is it dangerous to drive with a P0720 code?
A: Driving with a P0720 code can be risky. The transmission may not shift properly, potentially leading to jerky driving and potential damage to the transmission itself.
Q: How much does it cost to fix a P0720 code?
A: The cost of fixing a P0720 code can vary depending on the specific issue. A new OSS can cost anywhere from $50 to $200, while wiring repairs can cost less. More complex issues, such as a faulty TCM, could be more expensive.
Q: What are some other OBD II codes related to transmission problems?
A: Besides P0720, other OBD II codes associated with transmission issues include:
- P0722: Output Speed Sensor Circuit Intermittent
- P0730: Incorrect Gear Ratio
- P0733: 3rd Gear Incorrect Ratio
- P0734: 4th Gear Incorrect Ratio
- P0735: 5th Gear Incorrect Ratio
Tips for Preventing P0720 Code
- Regular Transmission Fluid Changes: Regularly changing your transmission fluid can help prevent the buildup of contaminants that can damage the OSS.
- Avoid Overloading: Don’t overload your car, as this can put excessive strain on the transmission.
- Proper Maintenance: Regular maintenance of your car, including checking fluids and inspecting the transmission system, can help prevent future issues.
It is crucial to replace the output speed sensor with a compatible and high-quality part.
Need Help with P0720 Code?
If you’re struggling to diagnose and fix the P0720 code, don’t hesitate to reach out for expert help. Contact our team of experienced technicians for 24/7 support. We can help you troubleshoot the problem and provide guidance on the best course of action.
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