How to Fix Code P0155: A Step-by-Step Guide

AvatarByCarl Frisch

Code P0155 is a generic diagnostic trouble code (DTC) indicating an issue with the O2 sensor heater circuit. This code is most commonly caused by an electrical issue such as a fuse, wiring, or connector that is faulty. In order to fix this code, you will need to locate and repair the faulty part or parts.

The first step in fixing this code is to diagnose the cause of the issue. This can be done by using a diagnostic scanner to read the stored trouble codes and freeze frame data. The freeze frame data will provide information about what conditions were present when the code was stored and can help narrow down the possible causes.

Next, you should visually inspect all of the related wiring and connectors for any signs of damage or corrosion. If any damaged components are found, they should be replaced before proceeding further. Additionally, you should test all of the related fuses and relays for proper operation.

Once all of these steps have been completed and any necessary repairs have been made, you can clear the trouble codes from your vehicle’s computer system and test drive it to see if the code returns. If it does return, then further diagnosis will be needed in order to determine what is causing it.

Fixing Code P0155 in Automobiles

Understanding the Diagnostic Trouble Code (DTC)

Code P0155 is a generic diagnostic trouble code (DTC) that indicates an oxygen sensor heater circuit malfunction in Bank 2 Sensor 1. This code is associated with increased emissions, poor fuel economy, and a rough idle. It is important to diagnose and fix this code in order to reduce emissions, increase fuel efficiency, and avoid damage to the catalytic converter.

Checking the Engine Control Unit (ECU) Fuse

The first step in diagnosing and fixing code P0155 is to check the engine control unit (ECU) fuse. This fuse provides power to the O2 sensor heater circuit, so if it has blown then it will need to be replaced before attempting any further diagnostics or repairs. If the ECU fuse looks fine then it can be tested using a multimeter to ensure that it is providing power correctly.

Inspecting the O2 Sensor Heater Wiring Harness

The next step in diagnosing and fixing code P0155 is to inspect the O2 sensor heater wiring harness for any signs of damage or corrosion. If any of the wires are damaged or corroded then they should be replaced as soon as possible in order to avoid further issues with the O2 sensor circuit. Additionally, all connections should be checked for proper tightness and integrity in order to ensure that there are no loose connections which could cause issues with power delivery or other components of the vehicle’s electrical system.

Testing The O2 Sensor Heater Circuit Voltage

Once all wiring has been inspected and all connections have been verified, then it is time to test the voltage of the O2 sensor heater circuit with a multimeter. This test will tell you whether or not there is enough voltage present for the O2 sensor heater element to heat up properly. Ideally, this voltage should be between 0-12 volts depending on your vehicle’s specific make and model. If there is not enough voltage present then this could indicate an issue with either a shorted wire or a bad connection somewhere along the line which would need to be identified and repaired before attempting any further repairs on this circuit.

Replacing The O2 Sensor And/Or O2 Sensor Heater

If all tests have been completed and everything looks okay but you still have code P0155 present, then it may be time to replace either your oxygen sensor or your oxygen sensor heater element depending on what tests have indicated was causing your issue initially. Replacing either one of these parts can help reduce emissions and improve fuel efficiency while also helping prevent damage from occurring within your catalytic converter due to prolonged exposure of excess heat from faulty components within your system.

Preventing Code P0155 In Automobiles

There are several steps that can be taken in order to prevent code P0155 from occurring in automobiles such as regularly monitoring and replacing air filters, using quality fuel system cleaners, and inspecting wiring harnesses for corrosion or damage regularly. Additionally, it is important that you always use high quality parts when performing repairs on your vehicle as this can help ensure that everything continues working correctly for longer periods of time without having any unexpected issues arise such as DTCs like code P0155 appearing out of nowhere due to faulty parts being installed originally

Diagnosing the Code P0155

If your automobile is displaying a code P0155, you will want to determine what is causing the issue. The first step to take is to use an OBD-II (On Board Diagnostics) code reader. This device will tell you if your car is displaying a code P0155 and can also give you additional information about the issue.

Next, you’ll want to check if the oxygen sensor heater circuit is functioning properly. This involves inspecting all the wiring and connectors related to the oxygen sensor heater circuit and ensuring they are connected and free of any corrosion. You’ll also need to check for any broken or loose wiring that could be causing an interruption in communication with the oxygen sensor.

Repairing the Heater Circuit

If it’s determined that there’s an issue with the heater circuit, it’s time to start repairing it. First, you’ll need to locate where in the wiring harness the problem lies. This can be done by following each wire from one end of the harness to another, looking for any signs of physical damage or corrosion along the way.

Once you’ve identified which part of the harness needs repair, you’ll need to replace it or repair it as necessary. If you’re repairing a broken connection, then make sure that both ends are securely connected before moving on. If corrosion is present, then use some electrical cleaner or contact cleaner to remove it before reconnecting any wires or connectors that may have been affected by it.

Testing Oxygen Sensor Functionality

After making repairs or replacements to your oxygen sensor heater circuit, it’s time to test its functionality. To do this, connect your OBD-II scanner again and see if there are still any codes present that indicate a problem with the oxygen sensor heater circuit. If everything looks good, then start up your engine and let it run for a few minutes so that you can monitor how well your oxygen sensors are functioning with real-time data from your scanner.

If everything checks out okay, then congratulations! You have successfully repaired your automobile’s code P0155 issue! If not, then double-check all of your repairs and make sure nothing was missed during them before consulting a professional mechanic for further assistance.

FAQ & Answers

Q: What is Code P0155?
A: Code P0155 is a diagnostic trouble code (DTC) that indicates a malfunction in the O2 sensor heater circuit Bank 2 Sensor 1.

Q: What are the common symptoms of a faulty O2 Sensor Heater Circuit Bank 2 Sensor 1?
A: The common symptoms of a faulty O2 Sensor Heater Circuit Bank 2 Sensor 1 include poor fuel economy, check engine light, and rough idle.

Q: Why is it important to fix Code P0155?
A: It is important to fix Code P0155 as it can reduce emissions, increase fuel efficiency, and avoid damage to the catalytic converter.

Q: How can I prevent P0155 in automobiles?
A: You can prevent P0155 in automobiles by regularly monitoring and replacing air filters, using quality fuel system cleaners and inspecting wiring harnesses for corrosion or damage.

Q: What are the possible causes of Code P0155?
A: The possible causes of Code P0155 include malfunctioning oxygen (O2) sensor heater element circuit Bank 2 Sensor 1, damaged or shorted oxygen (O2) sensor heater element circuit Bank 2 Sensor 1, defective oxygen (O2) sensor heater element circuit Bank 2 Sensor 1 and faulty engine control unit (ECU) fuse.

In conclusion, code P0155 can be fixed by first checking the O2 sensor for any signs of wear and tear, then replacing the O2 sensor if necessary and resetting the Check Engine Light. Additionally, a mechanic may need to diagnose the engine and fuel system to identify any other underlying problems. With proper care and maintenance of the vehicle, code P0155 should not be a recurring issue.

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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