AutoCodes – Honda – P0139 2008 Honda Accord

P0139 2008 Honda Accord Code - HO2S Bank 1 Sensor 2 Slow Response

Quick Answer

The Heated Oxygen Sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0139 2008 Honda Accord indicates HO2S Bank 1 Sensor 2 Slow Response.
Common causes: Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 11,438

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0139 2008 Honda Accord Description

The Heated Oxygen Sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

OBDII Code P0139 2008 Honda Accord - HO2S Bank 1 Sensor 2 Slow Response - AutoCodes.com — P0139 2008 Honda Accord Code - HO2S Bank 1 Sensor 2 Slow Response

What does this mean?

What are the Possible Causes of the DTC P0139 2008 Honda Accord?

Faulty Rear Heated Oxygen Sensor Bank 1
Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks may be faulty
Exhaust gas leaks

How to Fix the DTC P0139 2008 Honda Accord?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Replacing the Rear Heated Oxygen Sensor Bank 1 usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0139 2008 Honda Accord code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0139 2008 Honda Accord code?

Need more information on how to fix the P0139 2008 Honda Accord code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0139 2008 Honda Accord Code

1. What are the common symptoms of OBDII code P0139 on a 2008 Honda Accord?

The common symptoms of code P0139 include decreased fuel efficiency, rough idling, and an illuminated check engine light.

2. What does the HO2S Bank 1 Sensor 2 Slow Response code indicate on a 2008 Honda Accord?

The P0139 code indicates a slow response time from the downstream oxygen sensor (Sensor 2) in Bank 1 of the exhaust system in a 2008 Honda Accord.

3. What are the possible causes of a slow response from HO2S Bank 1 Sensor 2 on a 2008 Honda Accord?

Possible causes of a slow response from the oxygen sensor include a faulty sensor, wiring issues, exhaust leaks, or a problem with the engine's air-fuel mixture.

4. How can I diagnose the cause of the HO2S Bank 1 Sensor 2 Slow Response code on my 2008 Honda Accord?

Diagnosing the issue involves inspecting the oxygen sensor, checking for wiring faults, examining the exhaust system for leaks, and analyzing the air-fuel ratio using a scan tool.

5. How can I repair OBDII code P0139 on a 2008 Honda Accord?

Repairing the P0139 code may involve replacing the oxygen sensor, repairing any damaged wiring, fixing exhaust leaks, or addressing issues with the engine's fuel system.

6. Can the HO2S Bank 1 Sensor 2 Slow Response code cause engine performance issues on a 2008 Honda Accord?

Yes, a slow response from the oxygen sensor can lead to engine performance issues such as rough idling, decreased fuel efficiency, and potential drivability issues.

7. Is it safe to continue driving with OBDII code P0139 illuminated on a 2008 Honda Accord?

While it may be safe to drive with the code temporarily, it is recommended to address the issue promptly to prevent potential damage to the catalytic converter and ensure optimal engine performance.

8. Will resetting the check engine light resolve the HO2S Bank 1 Sensor 2 Slow Response code on a 2008 Honda Accord?

Resetting the check engine light may temporarily clear the code, but it will not fix the underlying issue causing the slow response from the oxygen sensor.

9. How do I prevent the recurrence of OBDII code P0139 on my 2008 Honda Accord?

Regular maintenance, such as inspecting and replacing oxygen sensors as recommended by the manufacturer, addressing engine performance issues promptly, and using quality fuel, can help prevent the recurrence of code P0139.

10. Can a DIY enthusiast repair OBDII code P0139 on a 2008 Honda Accord?

Depending on the DIY enthusiast's skill level and access to tools, it is possible to address some aspects of the P0139 code repair, such as replacing the oxygen sensor or checking for wiring faults. However, more complex issues may require professional assistance.