P1155 Lack Of HO2S21 Switch – Adaptive Fuel At Limit

As a car expert, I understand how frustrating it can be when your car is not running smoothly. One common issue that many car owners face is the P1155 error code, which indicates a lack of HO2S21 switch and adaptive fuel at limit. In this article, I will provide you with a step-by-step guide on how to fix this problem and get your car running smoothly again.

What is the P1155 Error Code?

The P1155 error code is a diagnostic trouble code that indicates a lack of HO2S21 switch and adaptive fuel at limit. This code is usually triggered when the oxygen sensor in your car’s exhaust system is not functioning properly. The oxygen sensor is responsible for measuring the amount of oxygen in the exhaust gases and sending this information to the engine control module (ECM). The ECM then uses this information to adjust the air/fuel mixture to ensure optimal engine performance.

Step-by-Step Guide to Fixing the P1155 Error Code

car vertical

Step 1: Check the Oxygen Sensor

The first step in fixing the P1155 error code is to check the oxygen sensor. Start by locating the oxygen sensor in your car’s exhaust system. It is usually located near the catalytic converter. Once you have located the oxygen sensor, disconnect the electrical connector and remove the sensor from the exhaust system.

Inspect the sensor for any signs of damage or wear. If the sensor is damaged or worn, it will need to be replaced. If the sensor appears to be in good condition, use a multimeter to test the sensor’s resistance. The resistance should be between 10 and 40 ohms. If the resistance is outside of this range, the sensor will need to be replaced.

Step 2: Check the Wiring

If the oxygen sensor appears to be in good condition, the next step is to check the wiring. Start by inspecting the wiring for any signs of damage or wear. If the wiring appears to be in good condition, use a multimeter to test the wiring for continuity. The wiring should have continuity between the oxygen sensor and the ECM. If there is no continuity, the wiring will need to be repaired or replaced.

Step 3: Check the ECM

If the oxygen sensor and wiring appear to be in good condition, the next step is to check the ECM. Start by disconnecting the electrical connector from the ECM and inspecting it for any signs of damage or wear. If the connector appears to be in good condition, use a multimeter to test the ECM for voltage. The voltage should be between 4.5 and 5.5 volts. If the voltage is outside of this range, the ECM will need to be replaced.

Step 4: Replace the Oxygen Sensor

If the oxygen sensor, wiring, and ECM all appear to be in good condition, the final step is to replace the oxygen sensor. Start by installing the new oxygen sensor into the exhaust system and reconnecting the electrical connector. Clear the error code using an OBD-II scanner and test drive the car to ensure that the error code does not reappear.

Conclusion

Fixing the P1155 error code can be a daunting task, but with the right tools and knowledge, it can be done. By following the step-by-step guide outlined in this article, you can diagnose and fix the problem and get your car running smoothly again.

FAQs

1. What causes the P1155 error code?

The P1155 error code is usually caused by a malfunctioning oxygen sensor or wiring.

2. Can I drive my car with the P1155 error code?

It is not recommended to drive your car with the P1155 error code as it can cause damage to your car’s engine.

3. How much does it cost to fix the P1155 error code?

The cost to fix the P1155 error code can vary depending on the cause of the problem. It is recommended to get a quote from a certified mechanic before proceeding with any repairs.