2G O2 Sensor Issue, How many wires?

[KieWhitehouse90]

Hello.
Bought a new O2 sensor (MD313819)
As I come to fit it today, I notice the one already on my car only has two wires (1 Blue, 1 White)
I've been trying to find some information on this so I can find the correct sensor I need, but I've had no luck, especially how the old sensor has no part number on it either (not that I can see at least)

From what I have read, all front O2 sensors for the 2G eclipse's have four wires, not two, so I am confused.

Can anyone give any info on this please?

Thanks for reading, I have attached a photo of my old sensor currently still in the housing.

Oh! and the car is a 2G 1995 GST A/T

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[nodoze]

yea mine has four wires , how many wires are going into your plug? i know some aftermarket 02 sensors have adapter harnesses

 

[fantom73088]

The front sensor should have 4 wires, for some reason the sensor you have now may not have a heater circuit if its a generic sensor. Which may be the DTC which pointed you to a faulty oxygen sensor in the first place. If the connectors fit and the code goes away consider it a win.

 

[KieWhitehouse90]

The wiring on the engine harness only has two wires for the oxygen sensor too, which I find really strange.

If every 2G uses heated O2 sensors, then both 2ga and 2gb engine harnesses should have four wires for the front O2 sensor to connect too.

Does anybody know if non-turbo 4g63's have heated O2 sensors or not?

I do not know much of whats happened to this car before I bought it, so I'm currently getting suspicious of all kinds of things !

 

[luv2rallye]

All DSM's (turbo or NT) have 4 wire heated O2 sensors. Your harness must have been changed for a 2 wire one. Follow it back and see if it connects to a 4 wire connector that's been hacked.

 

[KieWhitehouse90]

So this morning I have started following the two wires from the O2 sensor back to see what's going on...

But after 15 minutes I am already finding loads of mess where wires have been cut and all sorts!

The grey connector looks to be the knock sensor I think? That's been chopped up in the past..
The sensors in the thermostat housing have been chopped up too, and I am still yet to find the original four wires for the O2 sensor. The two wire connector on the right, with the black and white wires was what the O2 sensor was connected too.

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Any idea's to what on earth someone has been doing with this wiring loom?

I do not have a brilliant knowledge with electrics, but I need to fix this mess, any help would be appreciated !

 

[luv2rallye]

Maybe this will help some. The original harness 4 wire plug (ECU side) has wires white, black, yellow, red. On my 99 it's under the thermostat housing. The O2 side of the connector has many different colors depending on brand but usually the same 2 color wires are the heaters.

 

[ChristianEclipseAuto]

Hi I am having the same problem. My O2 Sensor only have two wires. Mine is the Japanese version (yes jap version)

I have gone through my ECU pins and found that I do have pin 60 (yellow) But in the connector to the O2 sensor is only blue and White.

Anybody solve this issue ?