You can find information about the P0137 fault code on this page.
It is one of the most popular fault codes that people search for on this website (in the top 50).
We have given it a seriousness of 4/10 with 1 being the least serious and 10 being the worst.
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Fault code P0137 is logged when the engine control unit (ECU) has detected an issue with the second oxygen sensor circuit in bank 1. This happens when bank 1 sensor 2 does not supply an output signal greater than 0.21 Volts.
A downstream oxygen sensor that cannot produce an output voltage this high is likely indicating excessive oxygen in the downstream exhaust system.
Heated oxygen sensors have internal heater systems to allow them to reach operating temperatures quickly as they monitor oxygen in the hotter exhaust system.
This downstream sensor is used to monitor the oxygen content after the catalytic converter.
Bank 1 refers to the side of the engine in which the number one cylinder is found. This applies only to V-shape engines. Sensor 2 is simply the downstream sensor.
Other Signs of This Problem
There are notoriously few signs that can help determine an issue with a downstream heated oxygen sensor. The signs for fault code P0137 are even fewer as the issue does not have any noticeable effects on driveability or the running of the vehicle.
This means it is very important to pay attention to the presence of the Check Engine light and subsequent fault codes.
What Could Be The Problem?
Most of the causes for P0137 are electronic in nature, relating to the low output voltage condition.
It is also possible that the engine is running lean, causing too much oxygen to be detected by the sensor. Running lean is when the engine has too much air in the air-fuel mixture.
There may also be a leak present somewhere in the exhaust, allowing for more air to enter and pass by the oxygen sensor.
A faulty oxygen sensor can also lead to this error being logged. Poor wiring or connections can also do this.
Like other heated oxygen sensor issues, the fixes for P0137 are all likely to be electronic in nature. This is especially true due to the low voltage condition.
However, if there is a leak present in the exhaust system it must be fixed to solve the problem. If there are any leaks present, they will likely be found before the oxygen sensor.
A faulty oxygen sensor should be replaced if there are any issues with it. Additionally, any poor wiring or connections should be replaced or fixed.
If the ECU is faulty or running on outdated software, it needs to be replaced or updated.
Fault code P0137 should be considered low in terms of seriousness. There is no risk involved to the vehicle and driveability is not affected.
It is recommended to have this issue solved within a few weeks. This is mostly due to poor emission levels and decreased fuel consumption.
In some cases, the catalytic converter can be at risk, which can be an expensive fix.
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