o2 sensor

P0137 Trouble Code – O2 Sensor Circuit Low Voltage

In OBD2 Trouble Codes by Magnus SellénLeave a Comment

o2 sensorWhat Does the P0137 Code Mean?

The word “bank” in the automotive world refers to the side of the engine. There are two banks inside the car: Bank 1 and Bank 2. In some cars, Bank 1 is the left side of the engine while Bank 2 is the right side of the engine. Generally, Bank 1 is the side where the #1 cylinder is located. To find out more about this, check our article Bank 1 vs Bank 2.

Code P0137 is generated when the engine control module (ECM) detects that the O2 oxygen sensor for Bank 1 voltage has remained below 400 millivolts (0.21 volts) for more than twenty seconds. Another reason for this code to occur is that the air/fuel ratio sensor remains lean mode for over 2 minutes. The duration varies from car to car.

ProblemSymptomsCausesSolutions
P0137 Trouble CodeCheck engine light

Engine idling
Rough

Fuel consumption increases

Bad smell coming from the exhaust pipe

Black some coming from the exhaust
Short voltage on O2 Sensor

Wiring issue with the O2 sensor circuit

Blown fuse for an O2 sensor

Vacuum leak

Excessive fuel pressure

Low fuel pressure

Defective Powertrain control module (PCM)

PCM software needs an update

Damaged Catalytic Converter
Replace the O2 sensor

Check for wiring and connections

Check resistance and voltage on the Oxygen signal circuit

Repair exhaust leakage near the O2 sensor

Update the PCM software

Check for damages and repair the catalytic converter

Replace the engine coolant temperature sensor

P0137 Symptoms

There are some common symptoms that you will experience when the P0137 code triggers or when the O2 sensor becomes faulty. If you want to find an more indepth guide about the symptoms, you can check it out here: Symptoms of a bad Oxygen Sensor (O2 Sensor). These symptoms include:

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Check engine light comes on
• Engine idling
• Rough performance
• Fuel consumption increases
• Foul smell coming from the exhaust pipe
• Black dust coming from the exhaust

In some cases, you might notice no symptoms at all.

Possible Causes

If your analysis tells you that the P0137 code has been triggered, it means that one of these following things may have happened:

• Malfunctioning O2 Sensor
• A short voltage on O2 Sensor
• Wiring issue with the O2 sensor circuit
• Blown fuse for an O2 sensor
Vacuum leak
• Excessive fuel pressure
Low fuel pressure
• Defective Powertrain control module (PCM)
• PCM software needs an update
• Damaged Catalytic Converter

Possible Solutions

Here are some of the things you can try to fix the error code:

• Replace the oxygen sensor
• Check for wiring and connections leading to the oxygen sensor
• Check resistance and voltage on the O2 signal circuit
• Repair exhaust leakage near the oxygen sensor
• Update the PCM software
• Check for damages and repair the catalytic converter
• Clean or replace the engine coolant temperature sensor

How to Diagnose the P0137 Code?

Before visiting an auto specialist, you should try a few steps to diagnose the problem yourself. Diagnosing the P0137 code is not difficult and we will explain to you some easy steps here.

Plug in the Car Battery Charger

Since we will be working with the ignition on, there is a possibility that the car’s battery will drain out. To avoid this, it is necessary that you connect a car battery charger to prevent additional problems that may arise from low voltage.

Connect the OBD2 Scanner

It is important that you have an OBD2 Code Scannerir?t=askamastermec 20&l=am2&o=1&a=B00UJV3E12, as it reads the information contained in the trouble code and helps you determine the root cause of the problem. It can be found easily on eBay or an auto shop for about $40. The more advanced ones are priced higher but offer better features.

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Check for Signs of Damage on the Sensor

Visually inspect the O2 sensor and check for signs of damage or corrosion. Also, check that the wiring is properly connected, i.e. there is no broken connection.

Check for Vacuum Leak

If there is a vacuum leak, too much air enters the combustion chamber, which leads to an engine misfire and the generation of the P0137 code. The best way to find a vacuum leak is with an EVAP Smoke Machine or a diagnostic tool. The best way to test is by checking the fuel trim reading on the scan tool. If a vacuum leak exists, the PCM will enable additional fuel to pass into the combustion chamber and the fuel trim reading should drop significantly (but not below 25%). This indicates that there is a vacuum leak.

Check Voltage of Sensor Using Digital Volt/Ohmmeter

Use a digital volt/ohm meter to test the O2 sensor’s voltage and determine if it is functioning correctly. The upstream heated oxygen sensor reading should vary between 100 millivolts and 900 millivolts once the engine reaches optimal temperature. If the reading does not seem to be in that range, there is a problem with the sensor.

Recommended Tools to Fix P0137 Code

It is a good idea to have the following tools handy when troubleshooting the P0137 code. You can easily find all these tools on eBay, Amazon or your local auto store.

Car Battery Charger
• Digital volt/ohmmeter
Multimeter
OBD2 Scanner

Oxygen Sensor Replacement Cost

The cost of replacing the oxygen sensor varies from car to car. The average cost comes to between $280 and $500. The sensor itself costs around $300, while the labor cost is estimated at between $40 and $100.

Does the P0137 Code Need Serious Attention?

It is always a good idea to take your car for repairs whenever the check engine light comes on. In the case of the P0137 code, it may not cause serious drivability issues, but it may reduce the car’s fuel economy and your vehicle will start emitting black smoke from the exhaust pipe. If the problem is ignored for too long, chances are that other engine components may get damaged as well.

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Can I Replace the Sensor Myself?

Yes! You can perform O2 sensor replacement procedure yourself provided that you have some expertise when dealing with automobiles. In general, you would require an advanced diagnostic scan tool, new O2 sensor, a jack to safely lift the vehicle propane torch, and some additional equipment. If you are a newbie, it is advisable that you take your car to a trained professional who can provide better guidance.

How Can I Prevent the P0137 Code?

You can prevent the P0137 code by ensuring that the O2 sensor remains free from dirt and contamination. Moreover, you should also check and fix vacuum leaks, as well as check if the wiring and connections are secured.

Further Questions?

If you have experienced the above symptoms and the problem still persists, let us know and we will give you some professional advice. Just comment below with your query and we will respond as soon as we can.

Hello I'm Magnus, the owner and the writer of this website. I have been working with cars since I was 16 and I'm specialized with in-depth Automotive diagnostics. Also been driving drifting for the last 6 years. I'm here to give you answers to all your automotive questions and I hope that you enjoy our content.

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