When you are swapping a OBDII engine into a OBDI chassis or similar Honda swap, it can be handy to know how to convert your oxygen sensor. If your Honda is equipped with a one wire 02 sensor, like the Honda Civic CX, or a seven wire wideband 02 found in the Civic VX, you’ll need to rewire and convert the oxygen sensor.
If you are swapping a DOHC VTEC or non VTEC B series engine into your Civic, you’ll need to convert your 02 sensor to a four wire unit for proper operation.
If you need to convert from a seven wire 02 to a four wire, or even a one wire 02 sensor to a four wire, our How To Convert Seven to Four Wire 02 DIY guide is for you. You will need wiring snips that preferably are made to cut through the 02 wiring, and vampire clips or metal clips to make the connections. Do not solder or attempt to solder your 02 wiring, as this can compromise the signal or performance of the unit.
Our instructions on How To Convert Seven to Four Wire 02 are all shown from the engine harness side, not the oxygen sensor flying loom. If you find the colors on your engine harness do not exactly match up, use the wiring positioning to finish your wiring job. These colors are for a 1992-1995 Honda Civic, if you are swapping into an Integra or Del Sol, the wiring position will remain the same.
How To Convert Seven to Four Wire 02
To successfully convert the seven wire 02 sensor in your Honda Civic to the four wire OBDII and OBDI four wire heated oxygen sensor setup we’re used to, inspect the diagrams below.
The wiring diagram for this seven wire wideband oxygen sensor are as follows :
- 1- White wire
- 2- Green wire with white stripe
- 3- Black wire
- 4- Yellow wire with black stripe
- 5- Orange wire
- 6- Orange wire with blue stripe
- 7- White wire with blue stripe
Now take the four wire oxygen sensor that you’ll be putting into your Honda swap, and take note of the wiring for this unit below.
The colors for this Honda four wire 02 sensor are as follows :
- 1- Green wire with white stripe
- 2- White wire
- 3- Orange wire with black stripe / OR Black wire with yellow stripe if using a Denso universal oxygen sensor
- 4- Yellow wire with black stripe
To begin our DIY how to convert guide, take your 02 sensor wiring and begin to cut into the seven wire 02 sensor you’ll be teeing into. Connect the following wires from your four wire 02 sensor to the seven pin 02 sensor connector.
Tee PIN 1 of the four wire oxygen sensor which is a green wire with white stripe, and connect this to PIN 2 or the green wire with white stripe on the seven wire plug.
Take PIN 3 of the four wire oxygen sensor, this wire is a orange wire with black stripe, or black wire with yellow stripe if you are using a Denso universal. This wire must be teed into PIN 4 of the seven wire plug that’s yellow with a black stripe through it.
You’re about halfway through our How To Convert Seven to Four Wire 02 DIY article, and to finish up the last half of your four wire 02 sensor, you will need to connect two more wires.
PIN 2 of the four wire 02 sensor is a WHITE wire that connects to the Orange wire with blue stripe on the seven pin connector. This is shown as PIN 6 on the seven pin VX oxygen sensor diagram above.
And lastly, you’ll be taking PIN 4 which is the yellow wire with black stripe and connect this wire to the yellow wires with black stripe on the oxygen sensor connector. This is your switched power source which provides the heater signal for your four wire oxygen sensor. This wire also powers your fuel injectors and idle air control valve as well.
Once you have completed all four wires, go ahead and tape up your connections after making sure they are secure. Fasten the wiring safely so that it won’t shake loose or become damaged, and you now know How To Convert Seven to Four Wire 02 Sensor for your Honda swap.