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P0137 is a diagnostic trouble code (DTC) for "O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
P0137 is the OBD-II generic code indicating the O2 sensor for bank 1 sensor 2 is failing to increase the voltage output above .21 volts indicating excessive oxygen in the exhaust.
This code occurs when the engine control module (ECM) sees the voltage of the O2 sensor for bank 1 sensor 2 below .21 volts when the ECM has commanded the fuel to a targeted rich condition on that bank of the engine.
The ECM detects the low voltage problem and turns on the Check Engine Light.
The ECM uses other O2 sensors to try and control the fuel injection with their values.
Scans codes and documents freeze frame data then clears codes to verify failure.
Monitors O2 sensor data to see if the voltage is switching back and forth between low and high at a fast rate compared to other sensors.
Checks the O2 sensor wiring and the harness connections for any corrosion in the connections.
Checks the O2 sensor for any physical damage or fluid contamination.
Checks for exhaust leaks before the sensor.
Follows the manufacturer's specific pinpoint tests for further diagnosis.
Follow these simple guidelines to prevent misdiagnosis:
Repair any exhaust leaks before the sensor to prevent excess oxygen getting into the exhaust stream causing the low voltage readings.
Check the O2 sensor for oil or coolant contaminants that could foul the sensor.
Repair any harness that is damaged properly to prevent erratic readings from the sensors.
Check the removed O2 sensor for damage from a broken catalyst and replace the catalyst if it has come apart.
The voltage output from the O2 sensor may be due to exhaust leaks causing the O2 sensors to give low output voltages.
The ECM cannot correctly control the fuel-to-air ratio of the engine fuel mixture if any O2 sensor is malfunctioning. This leads to poor fuel mileage and possible premature failure for some engine components.
Repairing or replacing the wiring or connection to the O2 sensor for bank 1 sensor 2
Repairing exhaust leaks before the sensor
The O2 sensor circuit for bank 1 sensor 2 is used to give a voltage feedback to the ECM showing how much oxygen is in the exhaust stream to help the engine control the fuel-to-air ratio better. The low voltage condition is excessive oxygen in the exhaust or problems causing the issue.
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