What Causes a P0137 Code? Here’s What You Need to Know

AvatarByCarl Frisch

A P0137 code is a diagnostic trouble code (DTC) that is stored in the engine control unit (ECU) when an issue with the oxygen sensor circuit is detected. The oxygen sensor circuit monitors the amount of oxygen in the exhaust and sends this information to the ECU so that it can adjust fuel delivery for maximum efficiency. When a P0137 code is set, it indicates that the voltage or signal from the oxygen sensor is lower than expected. This may be caused by a faulty oxygen sensor, a broken or damaged wiring harness, or an issue with the ECU itself.

What is a P0137 Code?

A P0137 code is a trouble code generated by the On-Board Diagnostic (OBD) system in an automobile. This code indicates that the oxygen sensor in the engine has detected a low voltage level. The oxygen sensor monitors the amount of oxygen in the exhaust system to ensure that the air/fuel mixture is at its optimal level for efficient combustion within the engine. A P0137 code could be triggered by a variety of different issues, including faulty wiring, faulty oxygen sensor connectors, damaged engine control units (ECUs), exhaust leaks, or vacuum leaks.

Common Causes of a P0137 Code

One of the most common causes of a P0137 code is an issue with the oxygen sensor itself. The oxygen sensor may be faulty or not functioning correctly due to age or wear and tear. Additionally, there may be an issue with the wiring harnesses and connectors for the oxygen sensor. These components can become corroded or damaged over time, which can lead to electrical issues and trigger a P0137 code. Another possible cause of this code is damage to an engine control unit (ECU). Finally, exhaust and vacuum leaks can also cause a P0137 code to be triggered as they will reduce the amount of oxygen detected in the exhaust system by the oxygen sensor.

Diagnosing a P0137 Code

In order to diagnose this trouble code correctly, it’s important to first use an OBD scanner to read and diagnose any other codes that may have been generated along with it. This will help narrow down any potential underlying issues that may be causing this particular issue. Once any other codes are ruled out, then it’s important to inspect all wiring and connectors associated with the oxygen sensor. Additionally, it’s important to look for any possible exhaust and vacuum leaks that may be affecting performance within your engine as these can also lead to electrical issues triggering this particular trouble code.

Repairing a P0137 Code

Once all other potential issues have been ruled out, repairing this particular problem usually involves replacing either the faulty oxygen sensor or its associated wiring harnesses and connectors depending on which one is causing the problem. Additionally, if any damaged components are found during diagnosis then these should also be repaired or replaced as necessary. If necessary, then you may also need to replace your engine control unit if it has been damaged in some way or another by this issue as well as sealing any possible exhaust or vacuum leaks that may have been identified during diagnosis.

Preventative Maintenance for Avoiding a P0137 Code

The best way to avoid having problems with your vehicle’s OBD system is through regular preventative maintenance checks on all components related to it such as regularly checking your vehicle’s oxygen sensors and inspecting wiring harnesses and connectors for any signs of corrosion or damage. Additionally, maintaining proper fuel/air mixtures within your vehicle will help keep your OBD system running efficiently as well as regularly checking for possible vacuum and exhaust leaks which could lead to electrical issues triggering codes like these in certain vehicles with certain systems installed on them.

What Causes a P0137 Code?

A P0137 code is an OBD-II diagnostic trouble code that indicates a problem with the oxygen sensor circuit in the exhaust system. This code is often caused by a faulty oxygen sensor, a wiring issue, or an exhaust leak. The oxygen sensor is responsible for measuring the amount of oxygen in the exhaust gases and sending this information to the engine control module (ECM). If the oxygen sensor fails or if there is an exhaust leak, it can cause the ECM to set this code.

Symptoms of a P0137 Code

When a P0137 code is present, it may be accompanied by several symptoms that can indicate that something is wrong with your vehicle. These symptoms include decreased fuel efficiency, reduced engine performance, and check engine light illumination. Additionally, you may also experience poor acceleration and rough idling. It’s important to have your vehicle inspected as soon as possible when these symptoms appear in order to determine the cause and prevent further damage to your vehicle’s engine.

How to Recognize a P0137 Code?

In order to recognize if you are experiencing a P0137 code, you should first check for any visible signs of damage or corrosion on the oxygen sensor wiring or connector. You should then use an OBD scanner device to read and diagnose the codes stored within your ECM. If you find that your vehicle has stored a P0137 code, it’s important to have your vehicle inspected by a qualified mechanic in order to identify and repair any mechanical issues that may be causing this code to be set.

Cost of Repairing a P0137 Code

The cost of repairing a P0137 code will depend on several factors such as labor costs and cost of replacement parts. In most cases, replacing the faulty oxygen sensor should rectify this issue and restore normal operation. Additionally, there may also be other repairs required such as replacing corroded wiring or fixing any exhaust leaks present in your vehicle’s exhaust system which will also add to the repair costs associated with fixing this particular diagnostic trouble code.

Safety Considerations During Repair of a P0137 Code

When working on vehicles with a P0137 code present, it’s important for you to take all necessary safety precautions in order to prevent any accidents from occurring while working on your vehicle’s engine components. Firstly, make sure that all necessary safety gear is worn at all times when working on vehicles such as work gloves, safety glasses and protective overalls. Additionally, make sure that you disconnect the battery before attempting any repairs on electrical components such as wiring or connectors as these can pose shock hazards if not done correctly.

Tips for Working on Automobiles with a P0137 Code

When attempting repairs on automobiles with this particular diagnostic trouble code present, it’s important for you to take some time beforehand and read through your service manual so that you have some idea about where certain components are located in order to replace them quickly and efficiently when needed during repairs. Additionally, try not to rush through inspections of electrical components such as wiring as they can easily be overlooked during quick inspections which could lead to further problems down the line if left unattended during repairs.

FAQ & Answers

Q: What is a P0137 Code?
A: A P0137 code is an oxygen sensor circuit low voltage code that indicates the oxygen sensor voltage output has dropped below the accepted level set by the manufacturer.

Q: What Are Common Causes of a P0137 Code?
A: Common causes of a P0137 code include faulty oxygen sensors, faulty wiring harnesses, damaged engine control units (ECUs), exhaust leaks, and vacuum leaks.

Q: How Can I Diagnose a P0137 Code?
A: To diagnose a P0137 code, you can use an OBD scanner to read error codes and inspect wiring and connectors for any damage. You should also check for exhaust and vacuum leaks that could lead to the code being triggered.

Q: How Can I Repair a P0137 Code?
A: To repair a P0137 code, you may need to replace the oxygen sensor or wiring harness, repair or replace any damaged components, and replace the ECU if necessary. You should also seal any exhaust or vacuum leaks.

Q: What Are Tips for Working on Automobiles with a P0137 Code?
A: Some tips for working on automobiles with a P0137 code include reading your service manual before attempting repairs and being thorough when inspecting components. Additionally, it is important to wear proper safety gear when working on automobiles and to disconnect the battery before beginning work.

In conclusion, a P0137 code is caused by the oxygen sensor having a low voltage output. This could be due to a faulty oxygen sensor, an exhaust leak, or an issue with the wiring or connections. It is important to properly diagnose and repair the issue in order to prevent further damage to the engine.

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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