What does code P0139 mean?

O2 Sensor Slow Response (Bank 1, Sensor 2): The downstream O2 sensor on bank 1 is responding slower than expected.

P0139 is rated as medium severity. Schedule service — affects performance or emissions.

P0139

O2 Sensor Slow Response (Bank 1, Sensor 2)

Powertrain Code · Medium

What does P0139 mean?

The downstream O2 sensor on bank 1 is responding slower than expected.

System: O2 Sensor

P0139 is a powertrain diagnostic trouble code indicating o2 sensor slow response (bank 1, sensor 2). This code is classified as medium severity, which means: schedule service — affects performance or emissions.

Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your vehicle.