Diagnosing Code P0139 on a Honda Accord – A Comprehensive Guide

AvatarByCarl Frisch

Code P0139 is a diagnostic trouble code (DTC) for an oxygen sensor circuit slow response (Bank 1, Sensor 2). This code is associated with Honda Accord vehicles that have the 2.4L (K24Z7) or 3.5L (J35Z6) engine. The oxygen sensor is located in the exhaust system and monitors the amount of oxygen in the exhaust gases. When the oxygen levels vary from what is considered normal, the engine computer will set a trouble code and activate the Check Engine Light on the dashboard. The P0139 code indicates that the oxygen sensor voltage has stayed below 400 millivolts for more than 20 seconds, indicating a slow response time in the oxygen sensor circuit.

Code P0139 Honda Accord: Diagnosis and Troubleshooting

What is Code P0139?

Code P0139 is an oxygen sensor circuit slow response trouble code that appears in most Honda Accords. It is a generic code, meaning that it applies to all makes and models of vehicles (1996-newer), although specific repair steps may vary depending on the model.

The code itself indicates an issue with the oxygen sensor circuit in the engine, which can be caused by a number of different issues, including faulty wiring or components, a faulty oxygen sensor, or an exhaust gas recirculation (EGR) valve issue. The oxygen sensor is responsible for monitoring the exhaust gases as they pass through the engine and sending signals to the Engine Control Unit (ECU) to make adjustments in order to maintain optimal engine performance.

How to Diagnose Code P0139?

In order to diagnose code P0139 accurately, a few steps should be taken. First, it’s important to check the O2 Sensor circuit for any faults or loose connections. This can be done with a digital multimeter (DMM) tool or a scan tool/code reader. If no faults are found here, then it may be necessary to check the heater circuit of the O2 Sensor for any issues. If this also checks out okay, then it may be necessary to test the functionality of the O2 Sensor itself using an OBD II scanner/reader. Finally, if all other tests come back okay, then it may be necessary to inspect the EGR valve for any signs of wear or damage that could cause this code to appear.

Honda Accord and Code P0139?

Honda Accords are no strangers to trouble codes like code P0139 and other O2 sensor related issues. Common problems with Honda Accords include faulty wiring harnesses that can cause misfires or intermittent power loss due to poor connections between components and faulty oxygen sensors that can cause poor fuel economy or erratic idle speeds due to incorrect readings from the sensors themselves. Additionally, EGR valves are known for becoming clogged with carbon deposits over time and causing an array of performance issues including this code appearing on your dashboard gauge cluster display.

Required Tools To Diagnose and Fix Code P0139 on a Honda Accord?

Fortunately, diagnosing and fixing code P0139 on your Honda Accord doesn’t require any special tools beyond what you would normally use when performing basic maintenance tasks on your vehicle such as changing oil or replacing spark plugs. Basic hand tools such as wrenches and screwdrivers will come in handy if you need to remove components from their housings in order diagnose certain electrical faults more accurately while a digital multimeter (DMM) will allow you measure current flow through various circuits more accurately than just visually inspecting them with your eyes alone. Additionally, having an OBD II scan tool/code reader will help you read live data from your ECU and quickly diagnose potential issues before they become major problems later down the road!

Common Causes of Code P0139 on a Honda Accord?

The most common causes of code P0139 on a Honda Accord are faulty wiring within the oxygen sensor circuit and failing heater circuits within the oxygen sensors themselves which can cause intermittent power loss due defective connection between components within those circuits as well as failing oxygen sensors that send incorrect readings back to your ECU resulting in poor engine performance and fuel economy overall. Additionally, clogged EGR valves can also result in this trouble code appearing intermittently due their inability provide proper exhaust gas recirculation into your engine’s intake manifold at certain times during operation which causes unmetered air entering into your combustion chambers resulting in uneven combustion events overall thus creating conditions where this trouble code could occur periodically while driving your vehicle around town day-to-day!

Cost of Replacing an Oxygen Sensor in a Honda Accord

Replacing an oxygen sensor on a Honda Accord can be quite expensive, depending on the year and model of your car. Labor costs typically range from $50 to $200, and parts prices can range from $100 to $400. The total cost estimation for replacing an oxygen sensor on a Honda Accord will depend on the specific make and model of the car, as well as any additional services that may be required.

How to Prevent Future Occurrences of Code P0139 on a Honda Accord

Code P0139 is an error code that indicates a problem with the oxygen sensor in your Honda Accord. To prevent future occurrences of this code, it is important to keep up with regular maintenance and adhere to proper driving habits. Regular oil changes, spark plug replacements and other routine maintenance tasks are essential for ensuring that your vehicle runs smoothly and efficiently. Additionally, driving habits such as avoiding rapid acceleration and deceleration, avoiding overloading the engine with cargo or passengers and following the manufacturer’s recommended speeds can help reduce the risk of code P0139 occurring again in the future.

Benefits of Fixing Code P0139 on a Honda Accord

Fixing code P0139 on your Honda Accord can provide many benefits. Improved fuel efficiency is one of the most notable benefits, as fixing this issue can help ensure that your engine operates efficiently and does not waste fuel unnecessarily. Additionally, fixing this code can provide enhanced performance due to improved air/fuel mixture ratios and other factors associated with proper oxygen sensor function.

Conclusion

In conclusion, it is important to take action when you receive code P0139 on your Honda Accord. This error code indicates a problem with the oxygen sensor which can have serious consequences if left unaddressed. Replacing the oxygen sensor may be costly but it offers many benefits such as improved fuel efficiency and enhanced performance. It is also important to adhere to regular maintenance tasks and practice safe driving habits in order to reduce the risk of any future occurrences of code P0139 in your vehicle

FAQ & Answers

Q: What is Code P0139?
A: Code P0139 is a diagnostic trouble code that indicates a problem with the oxygen sensor circuit in bank 1, sensor 2 of the engine. It is often accompanied by other codes including P0137 and P0140.

Q: What are the Causes of Code P0139 on a Honda Accord?
A: Common causes of Code P0139 on a Honda Accord include faulty oxygen sensor circuits, failing heater circuits, and defective oxygen sensors.

Q: What are the Symptoms of Code P0139 on a Honda Accord?
A: Symptoms of Code P0139 on a Honda Accord may include rough engine idle, lack of power, poor fuel efficiency, and illuminated check engine light.

Q: How Much Does it Cost to Replace an Oxygen Sensor in a Honda Accord?
A: The cost to replace an oxygen sensor in a Honda Accord can range from $250 to $400 depending on labor costs, parts prices, and other variables.

Q: How Can I Prevent Future Occurrences of Code P0139 on my Honda Accord?
A: To prevent future occurrences of Code P0139 on your Honda Accord, you should make sure to keep up with regular vehicle maintenance as well as practice good driving habits.

In conclusion, the code P0139 in a Honda Accord is a trouble code indicating an issue with the bank 1 sensor 2 oxygen sensor. In most cases, this is a sign of a faulty O2 sensor and will require replacement. However, other causes such as fuel delivery issues or exhaust system problems can also produce this code. It’s important to diagnose the underlying cause of the code before replacing any components to ensure that the problem is resolved and to avoid further damage to the vehicle.

Author Profile

Carl Frisch
Carl Frisch
With more than 30 years in the bicycle industry, I have a strong background in bicycle retailing, sales, marketing and customer service. I have a passion for cycling and a dedication to excellence. As a manager, I worked diligently to increase my capabilities and responsibilities, managing up to eleven mechanics (at Palo Alto Bicycles) and later as a working partner in my own store.

As the shop owner of Spoke n’ Word Cycles in Socorro, NM, the success of the mission was my responsibility, which I pursued passionately since we opened in 2003 through the spring of 2011. I am adept at managing owned and loan inventory, preparing weekly & annual inventory statements, and managing staff. The role as managing partner also allowed me tremendous freedom. I used this personal freedom to become more deeply involved in my own advancement as a mechanic, to spearhead local trail building, and advocating for cycling both locally and regionally.

As a mechanic, I have several years doing neutral support, experience as a team mechanic, and experience supporting local rides, races, club events. I consistently strive to ensure that bicycles function flawlessly by foreseeing issues and working with the riders, soigners, coaches and other mechanics. Even with decades of experience as a shop mechanic and team mechanic, and continue to pursue greater involvement in this sport as a US Pro Mechanic, and UCI Pro Mechanic.

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