P0142: O2 Sensor Circuit Malfunction (Bank 1 Sensor 3)
Can you still drive? Yes, this sensor is for emissions monitoring only and has minimal impact on engine performance. Repair at your convenience but before emissions testing.
What Does P0142 Mean?
Code P0142 indicates a malfunction in the third oxygen sensor circuit on Bank 1. Sensor 3 is located after the second catalytic converter on vehicles with dual-converter exhaust systems. This sensor provides additional emissions monitoring and its malfunction may trigger an emissions test failure without significantly affecting drivability.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Faulty O2 sensor
- Damaged wiring due to road debris or heat
- Corroded connector from exposure to elements
- Exhaust system leak near sensor location
Symptoms
- Check engine light on
- Failed emissions test
- No significant drivability issues
- Slight fuel economy decrease
Diagnostic Steps
- 1Read and document freeze frame data
- 2Verify the vehicle has a third O2 sensor location
- 3Monitor sensor voltage with a scan tool
- 4Inspect wiring and connector for physical damage
- 5Check for exhaust leaks near the sensor
- 6Replace the O2 sensor if confirmed faulty
Recommended Parts & Tools
oxygen sensor
O2 sensor socket
penetrating oil
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $60 - $350 |
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Chat with AI About P0142Commonly Affected Vehicles
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Frequently Asked Questions
Does my car have a Bank 1 Sensor 3?
Not all vehicles have a third O2 sensor. It is found on vehicles with dual catalytic converters in series, typically larger engines or vehicles meeting stricter emissions standards.
Is P0142 urgent?
No, P0142 is low severity. The third O2 sensor is primarily for emissions monitoring and its failure will not noticeably affect how your vehicle drives.
Community Fix Reports
Community reports are user-submitted and not verified by Auto AI Buddy. Results may vary.
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