Question

What is code P0037?

The P0037 code denotes “Heated Oxygen Sensor (HO2S) Heater Control Circuit Low (Bank 1, Sensor 2),” meaning there’s an issue with the downstream oxygen sensor’s heating element located on the back of the catalytic converter. The error code implies a low voltage in the rear oxygen sensor’s heater control circuit in Bank 1, Sensor 2.

The role of the oxygen sensor is to calculate the amount of oxygen in the exhaust gases after they leave the engine’s combustion process. For this information to be correct, the oxygen sensor should be at a particular temperature. Inside the oxygen sensor, there is a heater wire, which helps bring the sensor up to temperature faster. When the powertrain control module (PCM) notices the heater wire is not working, it will set the P0037 code.

What are the symptoms of the P0037 code?

These are the common signs that you can observe when the error code triggers in your car.

• The check engine light illuminates
• Your car fails the emissions test
• Decreased fuel economy
• Poor engine performance
• The car will have a rich running condition and probably black smoke
• Your car enters the failsafe mode and continues so until the issue is fixed

What can cause a P0037 code?

These are the common reasons why the code shows up.

• Faulty oxygen sensor
• Broken PCM heater circuit
• Heater control circuit problems, such as damaged wiring and poor connections
• Rusty connectors
• Poor ground connections
• Low battery voltage

How to fix the P0037 code

First, use a multimeter to check the oxygen sensor’s voltages and inspect its wires to ensure there’s no damage or corrosion. Then, follow these steps to fix the issue.

• Spray penetrating oil on the sensor.
• The sensor undergoes numerous heat/cool cycles and may be hard to remove. It’s better to heat it using a torch.
• Unplug the sensor’s electrical harness.
• Then, use a deep-well socket to remove the sensor.
• Compare the new and old sensors to make sure you have a precise match.
• Change the sensor and reconnect the electrical harness.
• Clear the error codes in the powertrain control module and start the car engine.

Can I drive with the P0037 code?

Technically, you can drive with this error code. But we don’t recommend it, as it shows an issue with your car’s oxygen sensor heater circuit. Driving your car for longer with this issue can lead to low fuel economy, poor engine performance, and possibly damage to the catalytic converter. So, get your car repaired by a skilled technician as soon as the error code is diagnosed.