P0137: Oxygen Sensor Circuit Low Voltage (Bank 1, Sensor 2)

The P0137 code stands for "Oxygen Sensor Circuit Low Voltage (Bank 1, Sensor 2)." This sensor monitors the oxygen levels in the exhaust to assess the efficiency of the catalytic converter, helping adjust the fuel-to-air ratio for optimal engine performance. This code appears when the engine control module detects that the voltage level from the downstream oxygen sensor (or O₂ sensor) on Bank 1 is too low.

Importance of addressing P0137

Resolving the P0137 code is important. A malfunctioning oxygen sensor affects fuel efficiency, increases emissions, and can lead to reduced engine performance. If left unaddressed, low voltage from the oxygen sensor can prevent the engine control module from correctly adjusting the fuel mixture. This issue leads to excess fuel consumption and could damage the catalytic converter.

Can I safely drive my car with this error code?

Driving with a P0137 code is possible but not recommended for long periods. Continued driving without repairs could also put stress on the catalytic converter, leading to costly repairs. The vehicle may experience reduced fuel economy, higher emissions and possible drivability issues.

Common symptoms of P0137

• Illuminated check engine light
• Decreased fuel efficiency
• Rough or unstable idle
• Increased exhaust emissions
• Hesitation or lack of power during acceleration

Diagnosing P0137

To diagnose the P0137 code, technicians follow these steps:

• Use an OBD-II scanner: Retrieve the P0137 code and any related codes that may provide further information.
• Inspect the oxygen sensor wiring: Check for damaged, corroded or disconnected wiring around the Bank 1, Sensor 2 oxygen sensor.
• Test the oxygen sensor: Use a multimeter to measure the sensor's voltage output, ensuring it meets manufacturer specifications.
• Examine the exhaust system: Check for leaks in the exhaust that could lead to inaccurate oxygen readings.
• Monitor live data: Review real-time data from the engine control module to confirm if the voltage from the O₂ sensor is within the expected range.

Repairing P0137

Some common ways to address the P0137 error code include:

1. Repair or replace wiring: Fix or replace any damaged wiring or connectors leading to the O₂ sensor.
2. Replace the oxygen sensor: If the sensor is faulty or has reached the end of its service life, replacing it can resolve the issue.
3. Fix exhaust leaks: Repair any leaks in the exhaust system to ensure accurate oxygen readings.
4. Check the engine control module operation: In rare cases, it might be necessary to reprogram or replace the engine control module if it fails to properly read or adjust to the sensor's output.
5. Clear code and test drive: After repairs, clear the code, and perform a test drive to ensure that the issue is resolved and the code does not reappear.

Related reading

Follow the link below to reach our diagnostic check engine trouble codes catalog:
On-board diagnostics (OBD-II) trouble code directory