Can a bad O2 sensor damage my catalytic converter?

Yes, a faulty O2 sensor can cause the engine to run too rich or too lean, which over time can damage the catalytic converter. Prompt O2 sensor replacement protects the more expensive converter.

How much does an O2 sensor replacement cost?

O2 sensor replacement typically costs $100-$400 including parts and labor. The sensor itself costs $20-$100, with labor varying based on sensor location accessibility.

P0143

O2 Sensor Circuit Low Voltage (Bank 1 Sensor 3)

Lowoxygen sensor

Overview

The P0143 diagnostic trouble code indicates a o2 sensor circuit low voltage (bank 1 sensor 3) condition. Oxygen sensors monitor the oxygen content in the exhaust stream and provide feedback to the PCM for precise fuel mixture control. A malfunction in the O2 sensor circuit can result in poor fuel economy, increased emissions, and potential catalytic converter damage.

Symptoms

Black smoke from exhaust
Poor fuel economy
Engine misfiring
Rough engine idle

Common Causes

Damaged O2 sensor wiring or connector
Contaminated O2 sensor (oil, coolant, or fuel additives)
Faulty O2 sensor heater circuit
Faulty PCM (Powertrain Control Module)

Diagnosis Steps

1Connect an OBD-II scanner and read all stored trouble codes and freeze frame data
2Monitor the O2 sensor readings using live data on the scan tool
3Inspect the O2 sensor wiring and connector for damage or corrosion
4Test the O2 sensor heater circuit with a multimeter
5Check for exhaust leaks near the O2 sensor location

Estimated Repair Cost

$100 — $400

Cost varies by vehicle, location, and repair shop. Includes parts and labor.

Commonly Affected Vehicles

Nissan SentraMazda 3Toyota CorollaVolkswagen Jetta

Related Codes

P0130 P0131 P0132

More Oxygen Sensor Codes

P0030HO2S Heater Control Circuit (Bank 1 Sensor 1)

Moderate

P0031HO2S Heater Control Circuit Low (Bank 1 Sensor 1)

Moderate

P0032HO2S Heater Control Circuit High (Bank 1 Sensor 1)

Moderate

P0036HO2S Heater Control Circuit (Bank 1 Sensor 2)

Moderate

P0037HO2S Heater Control Circuit Low (Bank 1 Sensor 2)

Low

P0038HO2S Heater Control Circuit High (Bank 1 Sensor 2)

Moderate

Frequently Asked Questions

Most O2 sensors should be replaced every 60,000-100,000 miles as preventive maintenance. Heated O2 sensors may last longer, but performance gradually degrades with age.