Error P0137 – how to fix?

Code Definition P0137

O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)

What does the code P0137 mean

• P0137 is a general OBD-II code which indicates that the O2 sensor for bank 1, sensor 2 is unable to increase the output voltage above .21V, indicating excess oxygen in the exhaust gas.
• This code occurs when the engine control module (ECM) sees the O2 sensor voltage for bank 1 sensor 2 below .21 volts when the ECM commanded fuel rich directed at that engine bank.

What causes the code P0137?

• The ECM detects a low voltage problem and turns on the Check Engine light.
• The ECM uses other O2 sensors to try to control the fuel injection with their values.
• Leaks from the exhaust system

What are the symptoms of the P0137 code?

• The engine will run lavishly as you test the sensors for problems.
• The Check Engine indicator light will come on.
• You may have exhaust gas leaks upstream or near the O2 sensor in question.

How does the mechanic diagnose the P0137 code?

• Scan the codes and document the data from the frozen frame, then erase the codes to verify the fault.
• Monitor the O2 sensor data to see if the voltage is changing between low and high at a rapid rate compared to other sensors.
• Check the O2 sensor wiring and harness connections for corrosion at the connections.
• Check the O2 sensor for physical damage and fluid contamination.
• Check for exhaust gas leaks upstream of the sensor.
• For further diagnostics, spot tests recommended by the manufacturer should be performed.

Common errors when diagnosing the P0137 code?

• Follow these simple tips to avoid misdiagnosis:
• Repair any exhaust leaks upstream of the sensor to prevent excess oxygen from entering the exhaust stream causing low voltage readings.
• Check the O2 sensor for oil or coolant contamination that could contaminate the sensor.
• Repair the damaged harness properly to avoid erroneous sensor readings.
• Check that the removed O2 sensor has not been damaged by a damaged catalytic converter, and replace the catalytic converter if it has been disconnected.

How serious is the P0137 code?

• The O2 sensor output voltage can be caused by exhaust gas leaks resulting in low O2 sensor output voltage.
• The ECM cannot properly control the engine’s fuel-to-air ratio if any of the O2 sensors are inoperative. This leads to low fuel consumption and possible premature failure of certain engine components.

What repairs can fix the code P0137?

1. O2 Sensor Replacement Bank 1 Sensor 2 Sensor 1
2. Repair or replace wiring or connection to O2 sensor for bank 1 of sensor 2.
3. Repair exhaust leaks upstream of the sensor

Additional notes regarding code P0137

The O2 sensor circuit for the bank sensor 1 2 is used to feed back a voltage to the ECM showing how much oxygen is in the exhaust stream to help the engine better control the fuel to air ratio. The low voltage condition is an excess of oxygen in the exhaust gas or the problem causing the problem.