P1143 Lack Of HO2S12 Switch – Sensor Indicates Rich

As a car expert, I understand how frustrating it can be to encounter car problems. One of the most common issues that car owners face is the P1143 Lack Of HO2S12 Switch – Sensor Indicates Rich error code. This error code indicates that there is a problem with the oxygen sensor in your car’s exhaust system. In this article, I will provide you with a step-by-step guide on how to fix this error code and get your car back on the road.

Understanding the P1143 Error Code

Before we dive into the solution, it’s important to understand what the P1143 error code means. This error code is related to the oxygen sensor in your car’s exhaust system. The oxygen sensor is responsible for measuring the amount of oxygen in the exhaust gases and sending this information to the car’s computer. The computer then uses this information to adjust the air/fuel mixture to ensure optimal performance and fuel efficiency.

When the P1143 error code appears, it means that the oxygen sensor is indicating a rich air/fuel mixture. This can be caused by a variety of factors, including a faulty oxygen sensor, a clogged air filter, or a problem with the fuel injectors.

car vertical

Step-by-Step Guide to Fixing the P1143 Error Code

Now that you understand what the P1143 error code means, let’s dive into the step-by-step guide to fixing it.

Step 1: Check the Oxygen Sensor

The first step in fixing the P1143 error code is to check the oxygen sensor. Start by locating the oxygen sensor in your car’s exhaust system. It’s usually located near the catalytic converter.

Once you’ve located the oxygen sensor, use a multimeter to test it. Set the multimeter to the voltage setting and connect the positive lead to the oxygen sensor’s signal wire. Connect the negative lead to a ground point on the car.

Start the car and let it idle. The multimeter should read between 0.1 and 0.9 volts. If the reading is outside of this range, it means that the oxygen sensor is faulty and needs to be replaced.

Step 2: Check the Air Filter

If the oxygen sensor is working properly, the next step is to check the air filter. A clogged air filter can cause the air/fuel mixture to be too rich, which can trigger the P1143 error code.

To check the air filter, remove it from the air filter housing and inspect it for dirt and debris. If the air filter is dirty, replace it with a new one.

Step 3: Check the Fuel Injectors

If the oxygen sensor and air filter are both working properly, the next step is to check the fuel injectors. A faulty fuel injector can cause the air/fuel mixture to be too rich, which can trigger the P1143 error code.

To check the fuel injectors, start by disconnecting the fuel injector harness. Use a multimeter to test the resistance of each fuel injector. The resistance should be between 11 and 18 ohms. If the resistance is outside of this range, it means that the fuel injector is faulty and needs to be replaced.

Step 4: Clear the Error Code

Once you’ve fixed the underlying issue that was causing the P1143 error code, the final step is to clear the error code from the car’s computer. To do this, you’ll need an OBD-II scanner. Connect the scanner to the car’s OBD-II port and follow the instructions to clear the error code.

Conclusion

The P1143 error code can be a frustrating problem to deal with, but with the right knowledge and tools, it can be easily fixed. By following the step-by-step guide outlined in this article, you can diagnose and fix the underlying issue that is causing the error code and get your car back on the road.

FAQs

Q: Can I drive my car with the P1143 error code?
A: It’s not recommended to drive your car with the P1143 error code. This error code can cause your car to run poorly and can lead to further damage if left untreated.

Q: How much does it cost to fix the P1143 error code?
A: The cost to fix the P1143 error code can vary depending on the underlying issue. If it’s a simple fix like replacing the air filter, it can cost as little as $20. If it’s a more complex issue like a faulty oxygen sensor or fuel injector, it can cost several hundred dollars.

Q: Can I fix the P1143 error code myself?
A: If you have some experience working on cars and the right tools, you can fix the P1143 error code yourself. However, if you’re not comfortable working on cars or don’t have the right tools, it’s best to take your car to a professional mechanic.