Honda P0139-Secondary HO2S Sensor Slow Response

Honda P0139 Secondary Heated Oxygen Sensor HO2S Sensor 2 Slow Response

Code P0139 Honda is DTC code indicating issue with heated oxygen sensor circuit in bank 1 sensor 2. The oxygen sensor is key component in the vehicle emission control system and used to monitor the amount of oxygen in exhaust gases. P0139 specifically indicates slow response in voltage output from secondary HO2S sensor.

Fault Location- Secondary HO2S Sensor

Possible Causes Code P0139 Honda

1.The most common cause of p0139 is faulty oxygen sensor. Faulty oxygen can causes the vehicle engine management system to send inaccurate amount of oxygen in the exhaust leading to incorrect fuel delivery.

2.Damaged wiring and connector of oxygen sensor result in slow response time from the sensor triggering p0139.

3.Exhaust leaks can obstruct with the proper functioning of oxygen sensor and trigger p0139.

4.Fuel system issue can cause the oxygen sensor to respond incorrectly and trigger p0139.

5.If catalytic converter is failing or not functioning properly it can cause p0139.

Honda P0139 DTC Code Possible Symptoms

1.Faulty oxygen sensor can cause incorrect fuel delivery resulting in poor engine performance and decreased engine power.

2.Incorrect fuel/air ratio can cause the vehicle to consume more fuel than normal and reduce fuel efficiency.

3.Incorrect fuel/air ratio can cause engine misfire and reduce overall engine performance.

4.Increased emission due to non-functioning of oxygen sensor circuit.

5.Engine check light illuminates on dashboard when p0139 stored in vehicle onboard diagnostic system.

How To Fix Code P0139 Honda

1.Inspect the oxygen sensor for any visible signs of damage. If oxygen sensor found damaged it need to be replaced.

2.Inspect wiring and connector of oxygen sensor any damaged or corroded parts need repaired or replace.

3.Check exhaust system to see any leaks that could be interfering proper operation of oxygen sensor any leaks found repair it .

4.Inspect fuel system to see if it is delivering correct amount of fuel. If Fuel system found not functioning properly repair it.

5.Inspect catalytic converter if it is not functioning properly catalytic converter need to be replaced.


Its important to have the vehicle inspected and diagnosed by professional mechanic to find and resolve issue related to p0139 for proper repair.

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