I purchased a new O2 Sensor for my 2001 Honda Accord and I cannot understand why it has a female plug and not a male plug as the existing one has so I assume I have to move the wires from the new unit to the old plug.

However, the old plug has 2 black, a white and a green wire and the new unit has 2 black a white and a blue wire.

Can I just connect the new wires to the old plug placing the blue wire where the green was?

  • Purchase the correct O2 sensor.
    – Moab
    Jan 17, 2019 at 22:53

3 Answers 3


Yes, it is possible.

The two black wires are probably the heater wires and you need to figure out signal polarity on the remaining two wires.

See Do I have to rely on wire color to correctly wire up an O2 sensor? for detailed steps on how to do this.

Before splicing in the new sensor, just make sure that the new sensor fits in the existing bung hole. This can be an issue if the new sensor is of the generic, model-agnostic variety.


and welcome to the forum.

You have to be very careful with these, but in this case yes, the Blue goes to Green. It would have been better if the parts supplier gave you the correct one to start with!

Here's a note from Denso, the main Japanese manufacturer of those sensors. If you read the chart, you'll see the green listed under 'old OEM sensor' and the blue under 'new Denso sensor' Link to PDF from Denso

  • I would caution against suggesting that blue maps to green. See the schematic in this question, where the blue does not map to green
    – Zaid
    Jan 24, 2019 at 6:54
  • @Zaid the schematic you refer to only shows sensors with no blue or green wires in the left hand column... so of course there's not an option for blue to green. I will admit that after 16 years of selling O2 sensors I still cringe at the idea of using a different sensor to the OEM one. As I said, it would have been better if the OP was given the correct one to start with.
    – Bevan
    Jan 24, 2019 at 18:10

You have the wrong sensor, return it and get the correct one

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