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P0139

Overview

Code

P0139

Code Type

P

Code Class

P0

System

Engine, Emissions

Severity Level

Low

Emissions Related

true

Drivability Impact

None

Diagnostic Protocol

OBD2

Freeze Frame Useful

true

Code Definition

Diagnostic trouble code P0139 indicates a slow response from the oxygen sensor circuit for Bank 1 Sensor 2

Symptoms

Check Engine Light illuminated

Overview applies to this diagnostic code.

Affected Systems

On This Page

  • Code Definition

  • Symptoms

  • Affected Systems

  • Possible Causes

  • Diagnostic Steps

  • Drive Safety Notes​

More Resources

Slow downstream O2 response affects catalyst efficiency monitoring

Possible Causes

Aging oxygen sensor

Diagnostic Steps

1 Confirm the fault code; 2 Monitor sensor response time; 3 Replace the oxygen sensor if slow response is confirmed

Drive Safety Notes

Driving is safe, but emissions monitoring accuracy is reduced

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