Code P1143 CADILLAC: Causes, Symptoms, and Repairs
1. Meaning of Code P1143 CADILLAC
The code P1143 is a diagnostic trouble code (DTC) related to the oxygen sensor (HO2S) Bank 1, Sensor 3.
Function of the Oxygen Sensor (HO2S)
- It measures the amount of oxygen in the exhaust gases.
- It sends this information to the engine control module (ECM).
- The ECM then adjusts the air-fuel mixture to optimize combustion.
- A voltage that is too low means the sensor is not working correctly.
This code can indicate a problem with a faulty HO2S sensor or damaged wiring.
2. Possible Symptoms of Code P1143
- Check Engine Light illuminated
- Increased fuel consumption
- Irregular idle
- Increased pollutant emissions
3. Possible Causes of Code P1143
Code P1143 can be caused by:
- Faulty oxygen sensor (Bank 1, Sensor 3)
- Open or short circuit in the HO2S sensor harness
- Poor electrical connection in the HO2S circuit
4. How to Repair Code P1143 CADILLAC?
1. Check the condition of the wiring and connectors
- Visually inspect the HO2S sensor harness.
- Look for cut, melted, or corroded wires.
- Check the connector pins (broken, bent, or corroded).
2. Test the oxygen sensor with a multimeter
- Disconnect the sensor and measure the voltage with a multimeter.
- The voltage should vary between 0.1V and 0.9V when the engine is hot.
- If the voltage is stuck or absent, replace the sensor.
3. Check the sensor signal with an OBD-II scanner
- Read the HO2S sensor’s real-time values.
- If the values remain constant, suspect a faulty sensor.
4. Clear the Code and Test the Vehicle
- Clear the error code with an OBD-II scanner.
- Perform a road test to check if the code reappears.
Conclusion
The code P1143 CADILLAC is often caused by a faulty oxygen sensor or a wiring problem. An accurate diagnosis following the steps above will resolve the issue and improve engine performance and fuel consumption.