Folks,

I have some questions about an ECU swap I want to preform. I have a 1997 auto and a 1999 manual parts car. I am taking the mt out of the 99 and swapping it into my 97. I want to use a 96 mt JWT ECU which will complement the 00VI I will put on. I notice that the rear O2 sensors are different from 96 to 97. The different being a three wire versus four wire design. Also I notice that on a 96 ecu, the O2 heater and sensor pins are different for the rear sensor than on the 97 ecu.

I would appear to me that the difference between three and four wire narrow band sensors is simply a dedicated sensor ground reference. But the reason that people with 96 ecus get rear O2 sensor codes in their 97+ cars is that the pins on the harness are in difference locations. For model year 1996, the analog voltage is carried to the ecu on pin 56 and the heater control is done on pin 105. These pins correlate to 56 and 107 respectively on a 97.

Is this a correct assumption? Do I just have to swap a pin to run CEL free in my 97 with a 96 ecu?

 

You're correct. There are a couple of ways to remove the 0707 rear o2 sensor code. Easiest way is to move pin 107 to pin 105 on the harness and ground pin 112. Apparently the desired results varied but it did work with a '96 TS ECU on my '98.

The other method involved swapping out the 4-wire o2 sensor (zirconia) for a 3-wire (titania) but the titania type sensor apparently is difficult to source.

I believe there's a thread by eng92 which covers this in depth.

 

Excellent, thank you. I didn't notice pin 112 before. I will check out that thread.