P CODES (POWERTRAIN) P0100 - P0199 P0137

Definition of Trouble Code P0137

Trouble code P0137 refers to a malfunction in the oxygen sensor circuit, specifically indicating low voltage in the downstream or post-catalytic converter oxygen sensor (Bank 1 Sensor 2). The oxygen sensor plays a crucial role in measuring the amount of oxygen in the exhaust gases, helping the engine control module (ECM) maintain the correct air-fuel mixture for optimal engine performance and emissions.

Diagnosing Trouble Code P0137

Before beginning the diagnosis process, make sure to gather necessary tools such as a digital multimeter, scan tool, and a repair manual specific to your vehicle. Follow these steps to diagnose the P0137 trouble code:

1. Connect the scan tool to your vehicle's OBD-II port, typically found under the driver's side dashboard. Turn the ignition key to the "ON" position, but do not start the engine. Use the scan tool to confirm the P0137 code is present.

2. Visually inspect the wiring and connectors related to the oxygen sensor for damage, corrosion, or wear. Damaged or corroded wires can cause low voltage readings.

3. Using the digital multimeter, check the voltage on the oxygen sensor signal wire. Consult your vehicle's repair manual for the correct specifications. If the voltage is within the specified range, proceed to the next step. If not, replace the oxygen sensor and retest.

4. Check the oxygen sensor's heater circuit by measuring the resistance across the heater terminals. Refer to your repair manual for the correct specifications. If the resistance is out of range, replace the oxygen sensor.

5. Inspect the ground connection for the oxygen sensor. A poor ground connection can cause low voltage readings. Clean the ground connection if necessary, and retest.

6. If all previous steps have been completed and the issue persists, the problem may lie within the engine control module (ECM). Consult a professional mechanic or your vehicle's repair manual for guidance on testing and replacing the ECM if necessary.

Repairing Trouble Code P0137

Based on the diagnostic steps, follow these guidelines for repairing the P0137 trouble code:

1. If damaged or corroded wiring was found during the inspection, repair or replace the affected wires and connectors. Clear the trouble code using the scan tool and retest to ensure the issue has been resolved.

2. If the oxygen sensor is found to be faulty, replace it with a new one. Clear the trouble code and retest to ensure the issue has been resolved.

3. If a poor ground connection was identified, clean and secure the connection. Clear the code and retest to ensure the issue has been resolved.

4. If the ECM is determined to be the cause, consult a professional mechanic or your vehicle's repair manual for guidance on replacing the ECM. After replacement, clear the trouble code and retest to ensure the issue has been resolved.

Conclusion

Trouble code P0137 is related to low voltage in the oxygen sensor circuit (Bank 1 Sensor 2), which can affect engine performance and emissions. By following the step-by-step diagnostic and repair procedures outlined above, you can identify and resolve the issue. However, if you are uncertain or uncomfortable performing these tasks, it is recommended to consult a professional mechanic for assistance.