P0142

Q: What does OBD2 code P0142 mean?

P0142 means: O2 Sensor Circuit Malfunction Bank 1 Sensor 3. The third oxygen sensor position on Bank 1 (found on some V6/V8 engines with dual catalysts) has a circuit fault.

O2 Sensor Circuit Malfunction Bank 1 Sensor 3

The third oxygen sensor position on Bank 1 (found on some V6/V8 engines with dual catalysts) has a circuit fault.

SeverityMinor

CategoryEmissions

Est. Repair Cost$100-$350

Code TypePowertrain

DIY RepairYes

⚡ Common Causes

›Faulty O2 sensor
›Damaged wiring
›Exhaust leak near sensor

⚠️ Symptoms

›Check engine light
›Possible failed emissions test

✅ How to Fix — Step by Step

Step 1:Inspect sensor wiring and connector
Step 2:Check for exhaust leaks
Step 3:Test sensor voltage
Step 4:Replace sensor if faulty

🔧 Diagnostic Tools Required

✔OBD-II Diagnostic Scanner
✔Digital Multimeter
✔Basic Hand Tools
✔Flashlight
✔Vehicle Service Manual

Using the correct diagnostic tools helps identify the root cause of P0142 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.

💡 Pro Tip: Sensor 3 positions exist mainly on engines with a secondary catalytic converter downstream of the main one - confirm your engine layout before ordering parts.

Repair Cost Estimate

Full Repair Estimate

$100-$350

DIY Possible?

YES

Severity

Minor

Frequently Asked Questions

What does OBD2 code P0142 mean?+

P0142 stands for O2 Sensor Circuit Malfunction Bank 1 Sensor 3. The third oxygen sensor position on Bank 1 (found on some V6/V8 engines with dual catalysts) has a circuit fault.

What causes code P0142?+

Faulty O2 sensor; Damaged wiring; Exhaust leak near sensor

How do I fix code P0142?+

Inspect sensor wiring and connector; Check for exhaust leaks; Test sensor voltage; Replace sensor if faulty

How much does it cost to fix P0142?+

Estimated repair cost for P0142 is $100-$350.

Is P0142 DIY-friendly?+

Yes — P0142 is generally DIY-friendly with basic tools.