OBD-II Code P0720 – Output Shaft Speed Sensor Circuit: An Overview
If you’re experiencing issues with your vehicle, and you see the dreaded check engine light on its dashboard, take a moment to breathe easy. In most cases, it is usually an easy fix, and one of the codes that you may encounter on modern vehicles is the OBD-II code P0720, which is related to the output shaft speed sensor circuit.
Therefore, in this article, we shall briefly explain what OBD-II is, what code P0720 means, how to diagnose and repair the issue related to this code, and answer some frequently asked questions related to the topic.
What is The OBD-II System?
OBD-II stands for On-Board Diagnostics, and it is an electronic system that monitors the performance of your vehicle’s engine and emission control systems. It was introduced in the 1990s and, since then, it is now standard in all cars sold in the United States since 1996.
The OBD-II system in your vehicle is responsible for detecting and reporting to you when something is wrong with your engine, and it does this by storing trouble codes that your mechanic can read to diagnose what the issue may be. Some codes can be minor and require simple solutions like tightening gas caps, while others can be severe and need immediate attention.
What is OBD-II Code P0720?
OBD-II Code P0720 is a trouble code that indicates that there is an issue with the output shaft speed sensor circuit. This code specifically refers to the sensor that monitors the rotational speed of the output shaft of the transmission.
The output shaft speed sensor’s primary function is to tell your vehicle’s onboard computer how fast your vehicle is moving based on the transmission’s output shaft. Your vehicle then uses this information in several ways, such as ensuring the transmission is in the correct gear, properly adjusting the torque converter lock-up, and calculating the speed of your vehicle for your speedometer.
If the OBD-II code P0720 is triggered, it could indicate that there is a fault or failure of the output shaft speed sensor circuit. The root cause may be due to a broken or faulty sensor, a damaged wiring harness, or a failing control module. The exact cause would need to be diagnosed by an experienced mechanic to determine what needs to be repaired or replaced to resolve the issue.
How to Diagnose OBD-II Code P0720
Before you start diagnosing the P0720 code, you’ll need to invest in an OBD-II scanner tool. These tools can be purchased online or at your local mechanic’s shop inexpensively, and they are worth the investment.
Once you have the scanner tool, the first step is to plug it in and read the codes. If code P0720 appears, your next step is to determine if the issue is the sensor itself or the circuit that the sensor is on.
To identify if it’s the sensor itself that is malfunctioning, start by looking for signs of damage or wear, such as bent or corroded pins. Check the wiring connections to the sensor, and ensure they are not damaged or corroded.
If the sensor and wiring are not damaged, the next step is to measure the sensor’s resistance with a multimeter. To do this, unplug the sensor connector and attach the red lead to one pin and the black lead to another. Compare the resistance value obtained to the manufacturer’s specifications for the sensor.
If these visual checks do not show any problems, then the issue is most likely in the circuit that the sensor is on, which could be caused by corroded or disconnected wiring. In this case, you need to check the entire circuit to find where the problem is coming from.
How to Repair OBD-II Code P0720
Once you have diagnosed the issue that triggered the P0720 code, the next step is to repair it. The precise action that needs to be taken depends on the root cause of the problem.
If the cause of the problem is a faulty sensor or a broken wire, then the preferred solution would be to replace the sensor or the damaged wire as required. In contrast, if the issue is with the control module, then it may need to be reprogrammed or entirely replaced.
It’s essential to understand that the repairs for P0720 can be simple or complicated, depending on the root cause of the issue. Therefore, if you’re not comfortable diagnosing and fixing the issue yourself, we highly recommend bringing your vehicle to your trusted mechanic.
Frequently Asked Questions (FAQs)
Q. I have just replaced the output shaft speed sensor on my vehicle, but the P0720 code is still coming up. What should I do?
A. If you have replaced the sensor and the code is still coming up, the fault may be in the wiring or the control module. Take your vehicle to a mechanic to diagnose and fix the problem.
Q. Can I drive the vehicle with a P0720 code?
A. Yes, normally, you can still drive your vehicle with a P0720 code, but we recommend fixing it as soon as possible. If left unfixed for a long time, it could cause serious engine or transmission issues and result in costly repairs.
Q. Where is the output shaft speed sensor located?
A. The output shaft speed sensor is usually located on the side of the transmission facing towards the rear of the car or the driveshaft. Its exact location can vary depending on the make and model of your vehicle.
Q. How much does it cost to fix a P0720 code?
A. The cost of fixing a P0720 code can vary depending on the root cause of the issue, but on average, it can cost between $100-$800. This cost includes labor costs, parts, and programming fees if applicable.
Q. Does a P0720 code always mean that there is an issue with the output speed sensor?
A. No, a P0720 code could also indicate that there is a problem with the actual circuit the sensor is on, such as corroded, broken wires or even a failing control module. It’s always best to diagnose and identify the exact cause of the trouble code to get an accurate fix.
Conclusion
OBD-II codes are always frustrating and confusing, but it’s crucial to understand that they are merely indications that something is going wrong with your vehicle. In the case of OBD-II code P0720, it’s usually due to an issue with the output shaft speed sensor circuit.
To diagnose and fix this problem, you need to start by investing in an OBD-II scanner tool, diagnosing the code’s root cause, and then repairing it. Remember, if you’re not comfortable fixing the problem yourself, you should always take your vehicle to a trusted mechanic for assistance.
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