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EmissionsMinor✅ DIY Friendly

P0155

O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1

Heater element fault in upstream O2 sensor Bank 2.

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

⚡ Common Causes

  • ›Failed heater element
  • ›Wiring fault
  • ›Blown fuse

⚠️ Symptoms

  • ›Check engine light
  • ›Slow cold-start response

✅ How to Fix — Step by Step

  • Step 1:Check fuse
  • Step 2:Test heater resistance
  • Step 3:Replace O2 sensor
  • Step 4:Check wiring

🔧 Diagnostic Tools Required

Using the correct diagnostic tools helps identify the root cause of P0155 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.

💡 Pro Tip: Heater circuit faults are more common in cold climates where sensors cycle more frequently.

Repair Cost Estimate

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

Frequently Asked Questions

What does OBD2 code P0155 mean?+
P0155 stands for O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1. Heater element fault in upstream O2 sensor Bank 2.
What causes code P0155?+
Failed heater element; Wiring fault; Blown fuse
How do I fix code P0155?+
Check fuse; Test heater resistance; Replace O2 sensor; Check wiring
How much does it cost to fix P0155?+
Estimated repair cost for P0155 is $150–$400.
Is P0155 DIY-friendly?+
Yes — P0155 is generally DIY-friendly with basic tools.

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