Does anyone have a 97-98 240SX, running a 95 transmission?

[iseenem240SX]

I was told after I paid for my MT swap that if I simply purchased a 5 speed ECU and installed it, all codes would disappear. After reading the write up at the top of the Tech forum pertaining to S14 swaps, I have my doubts. If I recall correctly, I have a '95 transmission, running the stock '98 auto ECU. From what I read, to stop throwing codes and stop the CEL from coming on, I should have used a '97-'98 transmission, and the same year ECU, this is because of changes in the OBD2 system. I also read that you can re-pin the ECU and change the O2 sensor from a 4-wire to a 3-wire. But I also read that there are some sensors "missing" on the '95 transmissions to allow a '97-'98 Engine/ECU to run without throwing codes. Does anyone out there have a '97-'98 240SX with a '95 transmission that isn't throwing codes?

[bartyb]

I have a USDM 98 240sx using a 95 MT, with a USDM MT 98 ECU, no problem, no codes. Didn't try using my Auto ECU though. The difference between the s13 and s14 trannies, is the crank position sensor for ODB2. So if you use an s13 transmission that doesn't have the whole and the sensor on top of the bellhousing, your engine check light will go on with the code for crank position sensor for obd2.

[iseenem240SX]

Thanks for the info. Est ce qu'il y a beaucoup de 240SX au Quebec?

[bartyb]

You're very welcome. And yes, there is a lot of 240sx's in Quebec, I have a fleet of my own, not so many kouki's though. You're french is pretty good

[iseenem240SX]

I just drove 100 miles on the ECU and my CEL came back on. I read on another post that if you run an OBD1 transmission on an OBD2 engine, you will throw a code and you have to wire a sensor on the transmission to the ECU. Do you know anything about this?

[bartyb]

To my knowledge, obd2 95 to 98 KA trannies are the same, they both have the obd2 crankshaft position sensor on the bellhousing. If you connected this sensor you should have no check engine light, if you didn't you would have an engine check right away, so my guess is that it's something else. Did you change anything else, if not, check the code, it might be with your wiring. Did you remove the A/T computer module located on the left side of the driver side (left of the steering wheel, near fusebox). Best thing to do is check the code, and we'll go from there.

[iseenem240SX]

No I didn't, just the passenger side kickpanel ECU. Wow goes to show how much I know about my car. I probably won't have time to do it today, but tomorrow morning I should be able to get to it. So what exactly do I have to do? Just unplug it and remove the entire thing?

[iseenem240SX]

I got a chance to look by the fuse box and there it was, what I am assuming is the A/T control module, looks like a little version of the ECU. I am not going to pretend like I know what I am doing since I did pay for the swap, I got what I thought was a good deal, it was $ 1300 for a 5 speed swap, new Competition Clutch, and J30 VLSD, that was installed, including labor and parts. The guy told me that he didn't have the ECU but that my car would run fine even though the CEL was on, he said that he had set it up so that all I had to do was swap the ECU and it would run perfectly, he didn't mention the control module. So if I remove it, everything should run as normal?

[bartyb]

If you use the A/T ECU that would explain the light, but you can always check what the code is.

And you are correct, the A/T control module looks like a smaller ECU, basically it's a metal box with wiring going to it.

The good way IMO to do a swap is to remove everything related to the A/T, from shift interlock cable, to all wiring, and properly conecting all sensors on the 5 speed transmission. Hopefully the guy who did the swap connected the reverse gear sensor or backing up at night will be a pain.

[iseenem240SX]

Everything works well, I removed the A/T control module, and went to Autozone for an OBD2 scan. I got three codes, 2 were the same and involved the knock sensor P0325 Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor); the other was P0705 Transmission Range Sensor Circuit malfunction (PRNDL Input). I have no clue where to go from here. The guy recommended I buy a new knock sensor, $140 at courtesyparts.com, or $ 60 on eBay, the other code baffles me because it seems it is A/T related, but I removed everything associated with the A/T. I am still running the A/T harness, do you think that might have anything to do with it?