A vehicle’s on-board diagnostics (OBD) has the capability to detect, identify, and log error codes—which contain 5 characters—that a mechanic or driver can trace using an OBD-II scan tool. These codes are designed to make it easier to diagnose and troubleshoot mechanical and electrical failures in your car.
However, having these codes won’t make a difference if you don’t know what they mean. So, if you’re getting the code P0720, this article will help you find out what it means, its causes, and the accompanying symptoms.
What Does the P0720 Code Mean?
Diagnostic trouble code (DTC) P0720 stands for “Output Speed Sensor Circuit Malfunction.” It means that the powertrain control module (or transmission control module) perceives a problem with the output speed sensor (OSS) or its circuit. The sensor in question is the one responsible for the display of real-time vehicle speed.
The powertrain control module (PCM) receives input from multiple sensors. One of these sensors is found on your transmission and is known as the speed sensor or transmission speed sensor.
There are two of these in every vehicle: one is called the output shaft speed sensor (OSS) while the other is known as the input shaft speed sensor (ISS). The latter measures the rotational speed of the torque converter/input shaft. It detects the internal revolutions of the transmission and sends the data to the PCM.
The OSS, on the other hand, monitors the rotational speed of the transmission output shaft. The data from this sensor is used to indicate accurate and real-time speed and distance readings on the speedometer and odometer.
You’ll commonly see this sensor mounted near the output shaft on the transmission.
The P0720 code is activated when the PCM detects insufficient input from the OSS. This code is similar to P0721, P0722, and P0723.
P0720 is a common issue among the following makes: Ford (especially a Ford F-150), Nissan, Dodge, BMW, and Honda.
What are the Possible Causes of the P0720 Code?
Here are the probable causes of code P0720:
- Faulty output shaft speed sensor
- Open or short in the electrical wiring or connections
- Malfunctioning PCM
What are the Common Symptoms of the P0720 Code?
The manifestations of a triggered P0720 code activated usually involve changes in the driveability of your car.
Here are the most common symptoms you may encounter if the PCM is detecting a P0720:
- Delayed gear shifting
- Malfunctioning speedometer
- Sometimes accompanied by P0715
How to Diagnose the P0720 Code
There are several possible causes that could trigger the P0720 code, so diagnosing it is not a straightforward affair. This is why a lot of people leave the job to their mechanics.
If you would prefer to do it yourself, however, watch these videos to get a better understanding of how to diagnose this code:
How to Fix the P0720 Code
As with diagnosis, fixing the P0720 code could be a little tricky since there’s no one-size-fits-all solution for resolving the code. You can have your mechanic do the fix for you or you can decide to go for it yourself if you feel like you have the required DIY skills.
If you’re planning on doing the latter, you’ll need to do some research. Once you’ve diagnosed the underlying cause, go online to find out what repairs other people (with the same vehicle as yourself) have employed to clear this code.
You should be able to find good information on forums and other similar platforms—just make sure to stick to the resolutions shared by owners of the same vehicle, as the appropriate fix for a P0720 may vary depending on make and/or model. A P0720 fix for a Ford, for instance, may not be the same as that of the repair you may need to do on a Nissan.
When you’re ready to perform the fix, make sure to check out repair manuals like the ones by Chilton or Haynes to figure out the proper steps for repairing your vehicle. You can also try a single-vehicle ALLDATA subscription that should help you with this and any other repairs you may need to do in the future.
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic.