I recently installed a 95 T/S Ecu in my 97 maxima. From what I understand the 95's only had 3 wires for the rear o2 sensor. I'm getting 0707 code. I purchased an o2 simulator but I'm not sure if I installed it correctly or if it would even get rid of the cel. Does anyone have any experience in removing the cel since 97's used 4 wires instead of 3.

 

I'm pretty sure that's one of the codes you can't avoid if you're using a 95-96 custom ecu on 97-99. The ecu is expecting to get 3 lines of data back, but it's getting 4 instead, so I doubt a simulator would work. I'll look for a 3-wire to 4-wire converter and get back to you.

EDIT: Quoted from boschautoparts.com:

If that helps you at all.

 

There's no way to trick the 95 ecu into thinking that its only seeing three signals instead of 4?

 

morning bump

 

to my knowledge there isnt. you should have used a ecu from a 97. 95s were OBD1 not OBD2 so i dont know how well that is going to go for you. i also would not be suprised at all if the two different year computers were programed completely different (in terms of software and communication over the network.) actually, since youre getting that code its a good indication that they is a good chance they do communcate differently. it sucks cause you probably spent a good chunk on that ecu. so there probably isnt anyway youre going to want to throw in a 97 now right?

 

95's are OBDII. I do agree with you about the difference in years though.

 

Well I got the ECU from someone else. Money is not the issue here. I'm throwing the question out there b/c my expertise is not electrical though I have some knowledge on how to read electrical plans. I'm going to look at 95 fsm and see if I can make heads and tails out of this. For now. I'm throwing in the old ecu for inspection.

 

wait whats wrong with the old one then?

 

There's nothing wrong with my 97 ecu. My 95 ecu is a TS G-Tech flash program. But given that its a 95 it doesn't recognize the rear 02 sensor. This is the only cel the ecu is giving me.

But it would be nice if I didn't have to switch ecu's during inspection or see a cel light while driving.

 

ohh alright, then why dont you just get the money back for the 95 and spend it on getting the chip in the 97?

 

I downloaded the 95 fsm. One thing that stands out from the two is the output voltage. The 95 registers 0 - 2.2 V where as the 97 registers 0 - 1.0 V. Also the sensors materials are different. The 95 is made of ceramic titania where as the 97 is made out of ceramic zirconia.

This means the cel is coming up b/c the ECU is not showing a maximum and minimum voltages. Since the voltages are not met the ecu will throw a code.

This might also explain why my 02 simulator is not working. B/c the simulator is sending voltages from 0 -1 V instead of the recommended 0 - 2.2 V. What yall think?

Other things I have found were the signals being sent to the ecm. On the 97 terminal 107 works like an on and off switch during different rpms. The ecm checks signals when its below 3600 rpm but when its above 3600 rpm it stops checking the rear heater signal. The terminal sees a voltage of 0 - 0.5 v.

The 95 doesn't use terminal 107. It uses terminal 105. And that sees a voltage of 0 - 0.2 V.

So, what you guys think. You think if I switch the 02 sensor to a 95 and than get 95 sensor connector will it work. The 56 terminal is the same so signal wise that should work. But I'm not sure about the 107 and 105 terminals.

Lastly, The ground seems to be different. Anyone has any advise on this too.

 

I got the ecu from another member. Technosquare doesn't reflash ecu's anymore. So that's out the question. Plus I have a rare ECU that they were able to raise the rev limit. That was only possible on the 95's.

 

ohh alright gotcha.

as for the 02 sensor problem...i believe 95 is 3 wire and 97 is 4 wire...which would pose a problem trying to connect a 95 to 97 connector. maybe you could try getting a 95 universal O2 and splicing the 2 ground wires to the 1 ground wire? dont know if that would work though...just a thought.


actually reading my notes....3 wire sensors have power wire, one ground, and one ground for the heater. while 4 wire sensors have 1 power one ground, and then one power for the heater and one ground for the heater. so on second thought youde have to splice the power wires together. which may give you a high voltage code for the 02 sensor...

so if i were you, i would try to rig anything up because i dont think it will work.