Fix P0720 Obd2 Code: Output Speed Sensor Malfunction

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How To Fix P0720 Obd2 Code?
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If you are experiencing issues with your car and see the P0720 obd2 code on the screen, don’t wait around to repair your vehicle’s faulty transmission. The P0720 code is a transmission error when a vehicle’s transmission is not functioning properly. It can cause the vehicle to malfunction unexpectedly and put your safety at risk.

P0720 Definition

The P0720 code stands for transmission fluid temperature sensor 2 circuit malfunction.

What does the P0720 code signify? The P0720 is a common OBD-II trouble error that indicates an issue with the output speed sensor circuit or input shaft speed sensor. Because the powertrain control module (PCM) relies on a signal from the output speed sensor, it can determine the best shift strategy and broadcast that information to the transmission. 

P0720 Meaning

P0720 Meaning:

When the transmission output shaft spins, it sends input and output shafts to an ECU. The output shaft speed sensor is near to but not adjacent to the drive axle, and the ECU uses it to monitor the transmission output shaft’s speed/RPM. When data from the OSS sensor does not meet predetermined parameters, the p0720 diagnostic code gets stored.

OBD-II Code P0720: Symptoms, Causes & Diagnose

Causes of p0720 Engine Code:

Here are a few of the causes of the p0720 error code:

  • Failed input speed sensor
  • Failed output speed sensor circuit malfunction 
    1. TFT sensor failure
    2. Broken or corroded connectors
  • Shaft speed sensor malfunction
    1. Wiring damage
  • Valve body
    1. Pressure related issues

Symptoms of Fault Code p0720:

If you are witnessing any of the following symptoms, you should take your car to a mechanic and have them inspect the transmission:

  • Check engine light: If it appears on your vehicle’s dashboard, it’s a good idea to have a mechanic diagnose it for you.
  • Transmission shifts too late or shifts too early: If your car is shifting into gears too early or too late, it may be because of transmission problems. Also, there must be a problem with input and output sensors.
  • Delayed, harsh, or erratic shifts: It could be because of a problem if the transmission hesitates a bit before or when you shift.
  • Increased engine noise: If you’ve noticed any higher engine noise in your car, that means the transmission may be causing problems as well.
  • Limp Mode: If you’ve noticed that your vehicle is not moving smoothly when you press the gas pedal, shaft position sensors mess can be a reason. 
  • Speedometer failure: If your speedometer is going haywire, it may mean that the transmission model is to blame.

How to Diagnose the code P0720?

While diagnosing a p0720 engine code, you should look for an additional DTC stored in the ECU. It will not only provide clarity but also help to discover the actual root cause of the problem. Besides that, they should also check the trans fluid as metallic debris can affect the sensor operation. 

After that, inspect the wiring harness and connectors to check for any damage or corrosion. If there is no issue, you should check the output shaft speed sensor with a voltmeter and oscilloscope. Finally, check the trans fluid temperature sensor and the gearbox input shaft speed sensor to complete the diagnosis.

Moreover, if there is still a problem, check the damn electrical connections of an OBD-II scanner. Take your diagnosis time to find the actual problem according to your engine type. 

Tools you need to diagnose code p0720:

To run the diagnostic code P0720 error code, the first step is to use a code reader like the generic OBD-II trouble code scanner and check if the “transmission” system is working fine. OBD-Ii code reader will help you read all required parameters within normal values. If you suspect any mechanical problems with the transmission system, it’s highly recommended to contact your mechanic who specializes in this area.

Common mistakes you must avoid when diagnosing P0720 code

Most P0720 Diagnostic trouble codes are diagnosed incorrectly by looking only at the transmission fluid and disregarding the influence that an ATF leak might have on the OSS sensor.

How to fix the p0720 obd2 code?

How to fix p0720 obd2 code?

There are several ways to fix the p0720 error code, and here are a few of these:

  1. Replace the output shaft speed sensor: The most common way to fix p0720 is by replacing the output speed sensor. This sensor looks like a plug and is connected to an electrical connector. However, before you start repairing your vehicle’s transmission, be sure to test the vehicle speed sensor first. The design of each speed sensor is different depending on the powertrain control feature. However, if the code persists, you can test the reference voltage and output speed sensor ground signal. 
  2. Replace the input speed sensor: This sensor is integrated into the transmission fluid temperature sensor. This is where the PCM will receive a boost of information. If the input speed sensor has failed, you can replace it with a new one by removing the transmission case. Moreover, also fix the TFT sensor
  3. Replace gearbox input shaft speed sensor: Another easy substitution allows the PCM to receive accurate transmission output speeds. Replace the faulty gearbox input shaft speed sensor with a new one if you encounter a p0720 error code.
  4. Repair or replace damaged wiring: If you’ve noticed any damaged wiring, that indicates that damage is already present. Then you should replace the damaged wires with new ones.
  5. Change transmission filter: If something has gone wrong with your transmission, you must first change the fluid and filter. Then, you should also check the transmission output shaft speed sensor with a meter.
  6. Fix transmission fluid leaks: Any trans fluid leak might also indicate that something is wrong with your transmission as well. However, it’s best to have a mechanic inspect to see exactly where the leak is coming from.
  7. Limp Mode: Fix the limp mode issue as soon as you notice it. If you’re unable to solve it, that means that your transmission has problems. So, get it fixed from the auto repair shop or transmission shops to fix fault code P0720. 
  8. Note: If you don’t know how to fix this error code, get an estimate for replacement transmissions from the certified mechanic and get it done. They will check the battery voltage, pulse signal, bulb replacement, body of transmission, and more to fix this issue. Moreover, it will take an average of 3-4 hours to fix the p0720 fault code


How to avoid the fault code p0720?

You can avoid the p0720 engine code by regularly changing your trans fluid and filter. Proper shifting is also crucial to avoid p0720. But, if you are encountering any issues with the transmission, be sure to have a professional mechanic inspect it for you.

Is DIY repair possible for engine code P0720?

Yes, the p0720 code can be repaired at home or by taking the vehicle to a transmission specialist or auto repair shops. In most cases, repairs can be done by following a DIY approach. Be sure to have the right tools like code reader and relevant parts.

Is the p0720 engine code serious?

P0720 is not a serious error code because it does not affect your vehicle’s drivability. However, it can be dangerous to ignore, so a professional mechanic always has it checked out.