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CarCodeFix
P0138Medium Priority

O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)

Category: Powertrain• Fuel and Air Metering

12 articles · 5 makes affected

What is P0138?

Oxygen Sensor Circuit High Voltage (Bank 1 Sensor 2). The downstream O2 sensor voltage is abnormally high, often indicating a failing catalytic converter.

Symptoms You May Notice

  • ●Check engine light
  • ●Sulfur smell from exhaust
  • ●Reduced fuel economy
  • ●Failed emissions test

How to Fix It

  • ●Replace catalytic converter ($500-$2500, professional)
  • ●Replace downstream O2 sensor ($100-$300, intermediate)
  • ●Repair exhaust leak ($150-$500, intermediate)

Owner Statistics

Based on 243,711 real owner discussions • 5819 confirmed solutions

Dataset (243,711 records)
$931
Average Repair Cost
2%
Success Rate
19%
DIY Repairs
243,711
Data Sources

About This Data

Statistics are aggregated from real owner discussions on Reddit, automotive forums, and YouTube comments. All data is anonymized and represents actual repair experiences reported by vehicle owners.

Issues by Vehicle