Codes/brands This Page Will Cover
- P0720 Output Speed Sensor Circuit
- P0721 Output Speed Sensor Circuit Range/Performance
- P0722 Output Speed Sensor Circuit no Signal
- P0723 Output Speed Sensor Circuit Intermittent
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What Is the P0720 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
The P0720 is an OBD code related to the workings and overall condition of the output speed sensor circuit. The Powertrain Control Module (PCM) in this particular circuit works by gathering a signal from the output speed sensor to assess and input the right shift strategy to the car’s transmission. This communication is critical, and any interruption or slow response will trigger the P0720 code.
For the vehicle’s PCM to operate as intended in this system, it needs to be able to detect multiple speed inputs and process them before sending the correct shift pattern to the automatic transmission in the vehicle. Firstly, the engine speed is determined from the crankshaft sensor in the engine. The PCM also measures the transmission input shaft speed during this process. Some transmissions use an intermediate shaft sensor, while all electronically-controlled automatic transmissions use an output shaft sensor (OSS) that can also act as the vehicle speed sensor in these situations. The OSS is located at the end of the output shaft and directly before the drive axles to obtain measurements of the shaft’s speed. Besides determining when to shift, these measurements are essential for the schedule for the torque converter engagement and the electronic pressure control (EPC) inside the transmission system. The PCM sets the P0721 code when it determines that the OSS is malfunctioning and sets the P0722 and P0723 codes when it cannot predict when to shift up and down correctly.
What Are the Symptoms of a P0720 Code?
The first symptom to expect when confronted with the P0720 code is the PCM setting the Check Engine Light in your vehicle. This is done to alert the driver of an issue with the engine or transmission. The physical symptom you will notice with P0720 or related codes is obvious shifting issues. This often goes along with a rough shift feel and misfiring from the engine. You may also find that your engine is stalling out when at a complete stop. Finally, your engine will experience a drop in fuel economy due to the engine misfires and poor shifting patterns by the transmission.
What Are Some Causes of a P0720 Code?
The most common cause of the P0720 code and its related codes is usually a defective or damaged output or input speed sensor. Sometimes, corroded wiring causes the code to set, as well as loose connectors surrounding either sensor. You may also find that contaminated transmission fluid will cause the PCM to trigger the code. Also, defective engine driveability sensors or shift solenoids are known to cause the P0720 issue. Finally, a damaged or defective PCM will be at the root of these issues, but this is less likely.
How Serious Is the P0720 Code?
The P0720 code doesn’t usually prevent a vehicle from driving altogether, but it can cause serious driveability issues. However, the effects of this code do get worse the longer it is left unaddressed. This means that you risk further damage to your engine and transmission by not inspecting the issue. You should take your car to a certified service center sooner rather than later so that you don’t cause further damage to your vehicle.
Can I Still Drive with a P0720 Code?
As we’ve mentioned, the P0720 code and its related codes can cause serious driveability issues, and you shouldn’t risk prolonged driving of your car. You may cause further damage to your engine and transmission that will only lead to remarkably high repair bills if the transmission is compromised. If your vehicle is experiencing rough shifting patterns, then you should take the steps needed to have it inspected by a qualified technician immediately.
How Easy Is It to Diagnose a P0720 Code?
The diagnostic process of the P0720 code requires a technician to use an OBD scanner to pull the associated codes and freeze frame data. The technician will then reset the codes and perform a road test with the vehicle to see if the codes return and determine if the issue is intermittent or with the output speed sensor. If the code still shows, then the technician will begin visually inspecting the associated wiring and connectors with the sensor. They will also check the transmission fluid to ensure that it isn’t low in volume or full of contaminants. The technician will then proceed to test and measure the output speed sensor’s ground signals and the reference voltage coming from the sensor. A common mistake made during this process is changing out the output speed sensor before ensuring that some other component isn’t at the root of the issue.
How Difficult Is It to Inspect a P0720 Code?
Because the inspection process of the P0720 code and its related codes requires multiple tests and visual inspection of specific components, this is best left to a qualified technician with prior experience working on these matters. It isn’t recommended to DIY this issue at home because you can easily misdiagnose the problem and repair the wrong part. Instead, a qualified technician will look to replace the output or input speed sensor if they cause the issue. They will also repair any wiring in the sensor system or replace connectors if damaged. A technician will also know to drain and then refill the transmission fluid to ensure this isn’t causing the P0720 code to appear. Finally, they may opt to replace the PCM if it’s damaged or defective.
Need Additional Help with Your P0720 Code?
The P0720 code and its related codes should be taken seriously, as we have shown in this guide. Of course, you don’t want to risk damaging your car’s transmission since replacing one is extremely expensive. However, if you follow the information, we have laid out here, you’ll be able to address the issue in time and keep your vehicle and its transmission shifting smoothly for longer.
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