VX o2 HF swap

[seeodywhy]

The wiring diag and the picture on autozones website have 7 wires attached to the sensor. The sensor I got with my motor has 5-wires and the ecu is a
P07-A00 can someone enlighten me please.

[seeodywhy]

I have seen other places on the internet with people asking about the o2 sensors. Some auto parts stores have 5-wire and others have 7-wires. Lots of people on this forum talk about havin 5-wire o2's but I can't seem to find any diagrams with 5-wire sensors.

[StorminMatt]

Well, the sensor itself has only five wires. BUT, there is also a trim resistor on the plug, which takes up two additinal pins. Thus, the '7-wire oxygen sensor'.

[seeodywhy]

On which two pins on the ecu does the resistor correspond, because the color codes on my diagram don't match. If I could get a picture of the back of the harness side of the plug I can figure it out.

[StorminMatt]

Originally Posted by seeodywhy

On which two pins on the ecu does the resistor correspond, because the color codes on my diagram don't match. If I could get a picture of the back of the harness side of the plug I can figure it out.

One of the resistor pins is connected to the green/white sensor ground wire that also grounds the TPS, CTS, IAT, and EGR lift sensor. This connects D22 at the ECU. The other resistor pin is connected directly to D3.

[SCoupe]

Civic VX oem plug

Originally Posted by StorminMatt

One of the resistor pins is connected to the green/white sensor ground wire that also grounds the TPS, CTS, IAT, and EGR lift sensor. This connects D22 at the ECU. The other resistor pin is connected directly to D3.

How are the internal resistors connected to anything given this pix?

[beb]

>>How are the internal resistors connected to anything given this pix?

The calibration resistor (singular) is inside the box-like area above the black and white wires and to the left of the yellow wire in that photo (in some of the counterfeit L1H1's, all that covers the cal resistor is some heat shrink as it just hangs out of the back of the connector). It doesn't in any way connect to the O2 sensor itself, but instead connects back to the ECU, which uses the value of this resistor to calibrate how it responds to signals from the O2 sensor - flip the connector around and you'll clearly see that there are two leads that head into this 'box'.

The cal resistor's value is picked at the factory, based on measurements taken of how the O2 sensor performs and is matched to it, and then packaged into the connector. The variability in the signal levels from O2 sensors is so wide that some sort of adjustment scheme like this has to be used. Bosch 5-wire O2 sensors use a cal resistor too, but in a very different circuit.