How to Fix P0121 OBD2 Error Code (TPS Circuit Range Issue)

Our vehicles today are very advanced. There are many sensors and codes that are involved. You will also find many intricate wiring designs as well. Remember, each component does something different. However, each component is important in its own way. Even with the highest-intelligence vehicle, there will still be error codes. In this article, we look at how to fix the error code P0121. 

Definition of Error Code P0121 OBD2: TPS (Throttle Position Sensor) A Circuit Range Performance Problem 

What Does Error Code P0121 Meaning? 

This is an error code that will appear when the Throttle Position Sensor has exceeded or fallen below a certain voltage. The ECM (Engine Control Module) will see that this is a problem. In return, the check engine light will come on, and you get an error code of P0121.

Error Code P0201: Symptoms, Causes & Fix

Symptoms and Causes of Error Code P0121

When error P0121 occurs, the check engine light will turn on. This appears on the dash. There will be many things that occur to your vehicle when this code is present. You will notice that the vehicle will jerk or knock. The top speed of the vehicle will be reduced. You will also find that the vehicle will not accelerate quickly, or it will stall randomly. (P0309 Obd2 Code)

You could find that the TPS or Throttle Position Sensor is faulty. The throttle could also be dirty. The body of the throttle could be faulty. There is an open or short in the Throttle Position Sensor. The connectors in the TPS sensor are not properly done. There is corrosion on the electrical components. 

Diagnosing and Repairing Error Code P0121 OBD2

This is something that is a little harder to repair and diagnose. It is a three out of five. We have made a list to best assist you in the diagnosing and repairing process. Following this list will help ensure that you are doing everything possible to fix your vehicle. 

1. Make sure that the only error code that appears is P0121. If possible, clear the check engine light and the error code. 
2. Ensure that you are checking the data that relates to the Engine Control Module. This will help you find the exact problem. 
3. Make sure that your Throttle Position Sensor has all wires properly connected. Visually check to ensure that all items are in good condition and where they should be. 
4. Clean the body of the throttle. It would be best if you did this whether you think your car needs it or not. This will not hurt you to do. If you have carbon built up, this can cause it to stick. A sticky throttle can send voltage that is not in the range it is supposed to be. 
5. If you are still having problems, remove the pipe from the body. This will be the intake pipe on the body of the throttle. 
6. You want to have throttle body cleaner. Spray a rag with this. (Be sure to use an old rag. This rag will not be used again for anything. It will be destroyed.) 
   1. Avoid putting cleaner directly into the throttle body. If you spray directly, it could cause damage to the inside components. Always spray onto a rag. 
7. Use your hands to open the body. You will do this by pulling the pulley on one side. If you have a different version, push the side of the body to open. 
8. Remove all black substances. This is carbon. You do not want this on the plate. You will do this until the plate and body are fully clean. 
9. Put everything back together and drive your vehicle. If the error code is gone, great! 
10. Suppose you find that you still have an error code. Make sure that you are looking at the Throttle Position Sensor. You want to make sure that there are no shorts. You want to make sure that the right voltage is going where it needs to be. 
11. If you find that you are not getting the right voltage, replace the Throttle Position Sensor. 

If you find that you cannot fix this yourself, take it to a mechanic. They will diagnose and fix the problem. It will be more expensive than doing it at home. 

If you have a newer vehicle, it will have an electronic throttle system. This process will not work for those that are electronic.

Avoiding Common Mistakes Made While Diagnosing P0121

Most people who have this error code will replace the Throttle Position Sensor or the body of the throttle. They do not even clean or attempt to figure out if it is something else. Save some money and look at the list above to help you better understand how to do this process at home. 

Is This Error Code Dangerous?

This is an error code that you should fix as soon as you can. It should be taken seriously. Your vehicle will have many issues with acceleration, and it can stall at any moment. This vehicle should not be driven until the error is fixed. It would be best to be towed to a shop if needed. Do not drive this to the mechanic. 

Avoiding This Error in the Future: To avoid this error code, keep up with your Throttle Position Sensor. You want to ensure that it is clean. Having this clean will ensure that you are ready to drive. It is also wise to ensure that all wires are connected and have power. You want the wires to be connected properly. 

Wrapping Up

Error code P0121 is a code that should be fixed now. The TPS may be faulty, or it could be something else related to the Throttle Position Sensor. You should always ensure that you are fixing the problem. If you fix this problem, you should not have to worry about it for quite some time. Always be safe when fixing vehicles and wear proper safety equipment.

Source: obd2pros.com