How to wire in an OBD2 port on 1NZ Charade?

[Hassan1991]

You can. Not sure if that will harm the sensor as the heater might always stay on.

[jdolondriz]

For the heater circuit, does it have a fixed resistance, regardless of whether it is hot or cold?

[Hassan1991]

Resistance is of coil. It will change but not like variable resistor.

[jdolondriz]

Btw, based on my understanding, heater of sensor 1 and sensor 2 would turn on at the same time and turn off at the same time?

[Hassan1991]

I'm not sure about that. It does make sense. But..
@Xulfiqar sir.

[Xulfiqar]

The oxygen sensor heaters are turned on by the ecu if the incoming sensor input slows down or goes wonky,

One some vehicles you will see a pid that says sensor temperature, it actually is the ecu measuring the amp pull of the heaters and showing a predetermined value,

Not all cars have all parameters though.

[jdolondriz]

Im trying to bypass it but so far the resistors ive used werent able to do this. I cant seem to get the correct resistance.

If I use a variable potentiometer, it is quite expensive here. Might as well just attach anothe ro2 sensor.

[jdolondriz]

@Hassan1991

I was looking at 1nz fxe manual and it says that p0037 code happens when it detects greater than 10.5v. is this the same with 1nzfe?

If this is so, can i tap 5volt reference instead of b+ to resistor to get less than 10.5v?

[Hassan1991]

No.
You can drop it down then 10.5v using variable resistor. Or make a voltage divider. With one fix value resistor and one variable resistor.

[jdolondriz]

Wouldnthe wattage of the resistor matter since it is a heater coil?

[Hassan1991]

Yes it does. 2 watt will work fine.

[jdolondriz]

wouldn't 2 watts burn since it would replace the supposed heater unit?

[Hassan1991]

Not replacing it. Just dropping volts to desire level.
Yes if you put it directly between B+ and HT wire. It will burn or something else will.
Or you can make a coil.

[jdolondriz]

do you have diagram on how i could lower the volts without placing it directly between B+ and HT?

Currently I have 2, 6(2 pcs), 12(2pcs) ohms wire wound 100watt resistors with aluminum cooling fins. Tapping them directly still results in the p0034 error.

[Hassan1991]

Why don't you just install an o2 hang it somewhere?

[faiz.sagor]

Hello, I am from Dhaka, Bangladesh. Recently I swap my old car engine. The technician skip to install DLC3 port. Now I am trying to install after watching so many doc and images. My ECU is 89661-12390 (may be its a Corolla 2002 ECU, not sure). I tried for a long month to communicate with ECU via CAN bus, K-line with various OBD2 Scanner, but failed. If any one have a correct wiring diagram of that CPU please share.

[Hassan1991]

Ecu communicates through K-line.
Please go through the thread. Diagrams being shared above.

[jdolondriz]

Hi again. Do you have full pdf of this? Thank you

[jdolondriz]

Can i connect the ht of sensor 1, to ht of sensor 2? Like doing a junction box. So that signal of ht sensor 1 will be used by sensor of ht sensor 2. Coz i checked ans ht of sensor 2 is sending pulsing signal

[Hassan1991]

No, i don't.
You mean you want to use one sensor for both inputs?