Edge

I need details on how to pull ECU codes on an '87. There is no CEL on, but the mpg is way down so I suspect the O2 sensor. Where is the ECU located and how do I access it? I've read there are several different ECU modes that needed to be selected by turning a screw on the ECU and then counting the LED flashes.

TIA

keith_u

the computer is under your passenger seat you have to take out the seat to get to it the best atleast i did.go here this will tell you more about how to use the on board control http://www.troublecodes.net/Nissan/pre88nssn.shtml

Edge

Where is the mode selector on the ECU? Is there a way to get to the mode selector without removing the seat. I see there is a plastic cover on the ECU that should be removed to get access.

keith_u

the selectors are on the inside of the box towards the center. That i know of there is no way to get to them with out removing the seat. But I may be wrong on that.

cardana24

iTrader: (81)

I just did this the other day so without reading anything this is the best I can remember. You need to take the screws out that hold the ecu to the floor. Slide the seat all the way back, and slide the ecu foward so it comes out of the black plastic shield. Once you have done this look on the driver side of the ecu and you will see the little screw and the indicator lights. While watching the light turn the screw all the way (I forget which way but it will only go one way). The green and red lights will blink together a certian number of times. Ever how many times they blink that is what mode you are in. You are going to want to be in mode 3, so as soon as the red and green flash 3 time together turn the screw all the way back to the position it started in. Now if you have stored codes they will flash out. Write down the number of green and red flashes. There can be more than one coded stored, so make sure you wait for the codes to make a full cycle. After you have written down all of the codes you need to take the ecu out of diagonostic mode, to do this turn the screw all the way back, and let it sit there for a few seconds, you will see the red and green lights flash very quickly (I forget the number of times they will flash but I think it is 3-5). After this has happend you turn the screw back to the starting position. And re-install the ecu back under the seat. Now go to your manual and see what the codes mean. Goodluck.

cardana24

iTrader: (81)

just tilt the ecu, and you have enough room to do every thing you need to do. Just make sure the seat is all the way back.