What is the P0131 Code?

The P0131 code is an indication that there is a low sensor voltage for the oxygen sensor bank one. It can also mean that the ratio of air and fuel is not right. It is the ECU that detects the problem as it detects the change of voltage in the oxygen sensor, and it also detects the change of air and fuel ratio.

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What causes P0131?

There are several reasons why the P0131 code occurs in your car. Here they are, and you should take note of them:

  1. Unplugged Wiring / Damaged Wiring – This problem can give out a terrible smell that you can smell from the exhaust. 
  2. Vacuum System Leakage – The leakage can cause the vehicle not to operate to its full potential. 
  3. Too High or Too Low Fuel Pressure – Fuel pressure is very important since too low fuel pressure can result in low horsepower. On the other hand, high fuel pressure can lead to an imbalance of the air and fuel ratio.
  4. Unupdated ECM or PCM – The problems cannot be detected right away if these are not updated.
  5. Oxygen Sensor Signal Circuit Resistance (Short, Open, or High). 
  6. Coolant Temperature Sensor’s faulty circuit. 
  7. Very old sensor – This is very common, especially for old cars and old models, since old cars have worn-out parts already. 

What are the symptoms of P0131?

As car owners, it is essential to note the symptoms of P0131 that may need your prompt action.

  1. When a bad smell comes from the exhaust, you need to have it checked.
  2. If you have observed a tough smoke in the exhaust.
  3. If you are having a hard start-up and the engine is running roughly
  4. Most of all, when the check engine light is activated.

These are just the common symptoms that your car can have and should prompt you to visit your mechanic. 

How can P0131 be fixed?

This problem can be diagnosed by a certified mechanic. Your mechanic needs two tools which are the OBD2 scan tool and the digital multimeter. 

The OBD2 scan tool is used to check for codes, just like the P0131. This tool is used because there may be other problem codes that need to be detected. Also, the codes that are seen should match the symptoms that are seen in your vehicle.

Moreover, the mechanic needs to check the oxygen sensor. A test has to be done to check for any problems. There should also be an ocular inspection on the oxygen sensor in case the trouble is caused by faulty wires or damaged connectors. The digital multimeter is then used to check the PCM or the ECM for any circuit problems.

What misleading actions can misdiagnose the P0131 Code?

The mechanic has to check the car as a whole and not just the oxygen sensor. Checking for some wiring issues and leaks in the vacuum can also be essential. If you have made your own personal observations of your car, you may report the problems you have seen to your mechanic.

How much would it cost me?

The cost of fixing the car with the P0131 code is about $100. However, the price also depends on the kind of car and the brand that you have. The P0131 will not cost you too much if you can detect the problem in advance. 

Is this a serious matter? How can the P0131 Code be avoided?

The P0131 code is a serious problem because it can lead to the inability of the car to run. So, with the symptoms present, it is highly advisable to consult a mechanic immediately. The cost will not be very expensive if the concern is addressed immediately. Also, the car owner has to do constant visual checks, especially for wires.

To prevent this trouble code from occurring, you can also apply anti-corrosive treatment to your engine. This is a preventive action. Also, it would be best if you were careful in checking or putting new wires since loose wirings can lead to further problems. 


 The P0131 code is another problem that your car can have. If this is not addressed immediately, it can result in more severe problems in the future. Having a stand-by mechanic is very important so that you can consult your car problems immediately and without any trouble.