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Accident Estimate
EmissionsModerate✅ DIY Friendly

P0133

O2 Sensor Circuit Slow Response Bank 1 Sensor 1

The upstream O2 sensor is not switching fast enough between rich and lean.

SeverityModerate
CategoryEmissions
Est. Repair Cost$150–$400
Code TypePowertrain
DIY RepairYes

⚡ Common Causes

  • ›Aging or contaminated O2 sensor
  • ›Oil or coolant contamination of sensor
  • ›Exhaust leak
  • ›Sensor past service life

⚠️ Symptoms

  • ›Poor fuel economy
  • ›Slightly rough idle
  • ›Check engine light
  • ›Failed emissions test

✅ How to Fix — Step by Step

  • Step 1:Replace upstream O2 sensor
  • Step 2:Check for oil or coolant burning
  • Step 3:Inspect exhaust for leaks
  • Step 4:Verify fuel trims are within range

🔧 Diagnostic Tools Required

Using the correct diagnostic tools helps identify the root cause of P0133 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.

💡 Pro Tip: O2 sensors typically last 60,000–100,000 miles — slow response is normal wear.

Repair Cost Estimate

Full Repair Estimate
$150–$400
DIY Possible?
YES
Severity
Moderate

Frequently Asked Questions

What does OBD2 code P0133 mean?+
P0133 stands for O2 Sensor Circuit Slow Response Bank 1 Sensor 1. The upstream O2 sensor is not switching fast enough between rich and lean.
What causes code P0133?+
Aging or contaminated O2 sensor; Oil or coolant contamination of sensor; Exhaust leak; Sensor past service life
How do I fix code P0133?+
Replace upstream O2 sensor; Check for oil or coolant burning; Inspect exhaust for leaks; Verify fuel trims are within range
How much does it cost to fix P0133?+
Estimated repair cost for P0133 is $150–$400.
Is P0133 DIY-friendly?+
Yes — P0133 is generally DIY-friendly with basic tools.

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