P0143 – OBD-II DTC

OBD-II DTC P0143 – O2 Sensor Circuit Malfunction (Bank 1 Sensor 3)

DTC P0143 meaning

DTC P0143 refers to a malfunction in the oxygen sensor circuit for Bank 1 Sensor 3. This code indicates that the Engine Control Module (ECM) has detected an issue with the signal from the oxygen sensor located in the exhaust system. The oxygen sensor plays a crucial role in monitoring the air-fuel mixture and ensuring optimal engine performance and emissions control.

DTC P0143 symptoms

Common symptoms associated with DTC P0143 may include:

• Check Engine Light illuminated
• Decreased fuel efficiency
• Rough engine idle
• Increased emissions
• Failed emissions test

DTC P0143 causes

Several factors can lead to the triggering of DTC P0143, including:

• Faulty oxygen sensor
• Wiring issues or damaged connectors in the sensor circuit
• Exhaust leaks near the sensor
• Contaminated or damaged sensor
• ECM malfunction

DTC P0143 seriousness

DTC P0143 is considered a moderate to serious issue. While it may not cause immediate engine failure, it can lead to:

• Increased fuel consumption
• Higher emissions, potentially leading to legal issues
• Long-term engine damage if not addressed

How to diagnose DTC P0143

To diagnose DTC P0143, follow these steps:

1. Use an OBD-II scanner to confirm the DTC and check for any additional codes.
2. Inspect the oxygen sensor and its wiring for visible damage or corrosion.
3. Test the oxygen sensor’s voltage and resistance using a multimeter.
4. Check for exhaust leaks near the sensor.
5. Examine the ECM for any faults or updates.

How to fix DTC P0143 step-by-step instructions

To fix DTC P0143, follow these steps:

1. Clear the DTC using an OBD-II scanner.
2. If the code returns, replace the faulty oxygen sensor.
3. Repair or replace any damaged wiring or connectors in the sensor circuit.
4. Fix any exhaust leaks that may affect the sensor’s readings.
5. Recheck the system with an OBD-II scanner to ensure the code does not return.

How to erase DTC P0143

To erase DTC P0143, you can:

• Use an OBD-II scanner to clear the trouble code.
• Disconnect the vehicle’s battery for a few minutes, then reconnect it (note that this may reset other systems).

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