DTC P0131 – How to Service Your Honda 02 Sensor

The DTC trouble code P0131 is for your Oxygen Sensor providing a value that is outside the values that your car manufacturer originally intended. The Oxygen Sensor (H02S) is designed to detect the oxygen content of your exhaust gases, providing a real time value to your ECU/PCM to control fuel consumption.

When your primary 02 sensor is faulty or there’s a short in the wiring leading to your 02 sensor, your ECU/PCM can trip the OBDII P0131 Trouble Code.

Today we’ll be looking at how to fix your P0131 Trouble Code in your 1997 Honda Civic DX. The Honda part number for this part is 36531-P2E-A01, Oxygen Sensor and we’ll be testing our Denso version of this unit.

This 02 sensor is connected by a 4 prong weather proof connector and the upstream 02 sensor is located in the catalytic converter in the Honda Civic DX headers. Your downstream 02 sensor is located further downstream of the exhaust, and does not affect gas mileage in the way your front 02 sensor does.

First connect your favorite scan tool or datalogger to determine the values being passed to your ECU from the front 02 sensor. Start the vehicle and let it idle until the cooling fans kick on and your vehicle has reached operating temperatures.

With your scan tool connected, read the values for the front 02 sensor during wide open throttle operation. Have a friend record what your 02 sensor is doing, while you drive on a safe road under wide open throttle conditions. If the voltage from your 02 sensor is .01 or less, try resetting your ecu to see if your DTC P0131 comes back.

If the voltage is .01 or less then there is an issue with your fuel filter, your fuel injectors or fuel pump. Check your fuel pressure and look in our How-to section to read more information about how to service those fuel components.

Check your 02 for a short.

1. Disconnect your 4 pin 02 sensor
2. Start engine and warm to operating temps
3. Read Primary 02 value using datalogger

If the value being read is .01 or less the next step is to check the wiring for a short. If the value is not .01 or less, you need to replace your narrowband Honda 02 Sensor.

Check your 02 wiring for a short

1.  Turn ignition to the off position
2. Disconnect the ECU connector D (16pin)
3. Check for continuity between the 02 sensor pin 1 and the Primary H02S sensor pin on the 16pin D connector for your Honda ECU.