Sorry that this has been banned and I am posting anyway. But the diagnosis procedure for late '99 maxima's must be different than in the FAQ's. The box is set up different. I need to get rid of my check engine light before I go for my emmissions test. I am fairly confident that one of the front heated O2 sensors set it off. Even disconnection of the battery won't get rid of the light now. I guess I could try that again though. One of these weeks I might remember to unhook the ground wire before bed after parking in a visitor space so that my wife can still get out in the morning before the 24 hours has lapsed.

But I would really like to know the proper procedure for diagnosing the idiot light. If you have any knowledge of the late '99 model's system please post. My guess is that it is the same or similar to 5th gen cars. But I havn't seen anything on the 5th gen forum for the ECU diagnosis.

Thanks,

James G

How to get the code:
http://vbxmaxima.8m.com/ecu.html

What the code means:
http://vbxmaxima.8m.com/ecudecoder.html



so this did not work?

What is the production date of your Maxima?


Is there a box behind the center console with a phillips head recessed hole towards the front of the car on the side of the ECU box?


If not, you need a scan tool which is discussed more thoroughly in the 5th gen forum. It isn't cheap.



My bare-bones GXE was made in 03/99 and has the normal ECU box.

I think the production date was Jan. '99. The box is in the same place as in the link. But the holes in the side are labeled differently and I think they are actually in different places. I have to go out soon to drop off my oil at the recycling center and make a few stops in town before the holiday. When I come back and it's a few degree's warmer I will look at the box again and then hit the link again. Afterwards I'll more fully explain the differences. I have gotten into the self diagnosis mode before, but It might have just been luck. If I can get my camera to cooperate I'll try to take a pic.

01/99 is the consensus production date as to when most 99 Maximas went to the 5th gen style ECU, which is not diagnosable manually. It can only be done with a scan tool.

That said, I haven't seen a GXE made on or after that production date that has had the 5th gen ECU, but I have noticed SE and especially SE-L Maximas here that have the 5th gen ECU.

My 99's ECU (SE) looks a good bit different than my 97's ECU (GXE) did. My 99's manf. date is 12/98 IIRC.

One of the holes should be coverd by a sticker. Inside of that there is a small, white screw. Unlike the directions you'll find at that site, you need to use a small, phillips head screwdriver. Also I've found that there isn't a stop point when turning the screw like there is in older models. I just turn it a few revolutions one way, and then a few back the other way.

Took me a while to figure it out too.

The procedure should be the same even on '99 ECUs. The screw is small and plastic rather the metal screw on previous ECus.

BTW resetting your ECU will fail you on your emissions. OBD-II vehicles have to be driven a few hundred miles after having the ECU reset (or battery replaced) in order to pass. This prevents people from resetting the ECU and passing emissions with trouble codes that haven't been set off yet.
-hype

Off the cuff here, but I believe you have to start and stop the car 10 or 20 times to eliminate the code(s) permanently.......Daniel B. Martin has mentioned this cycling before.....

Hmm never heard of that one, but that may be true. I just know from my experiences working at Carmax that cars which just had their battery replaced (or codes reset) will not pass emissions. After speaking with the tech who did the test, he said there are 3 markers which are only activated after driving a certain mileage.
-hype

Yet another problem with this issue. I am quite positive I can pass the emmisions portion of hte test. But, because of an idiot light I can't even take the test. What will the democrats think up next to interfere with a smooth, no hitch lifestyle?

My 99 SE-L ECU looks different from the one in the link too..Mine has a tiny white plastic screw about half-centimeter in diameter. But the method in the link works fine.

Same situation with my '99 SE-L. I had the instructions printed out and began to go to work under the gas pedal when I found that it was quite a bit different. Not only is the screw a tiny white plastic one, but it also says that it adjusts the idle. What's with that? I don't want to make idling adjustments. I only want to see why the hell my "service engine soon" light is one and reset it.
Have you guys had any success with this yet?

Thanks.

That would be the case I guess if the emissions inspector plugged into your ECU to check. NY State emissions have gotten alot more strict, they actually use a dyno to measure your car's emissions in all gears and every stage of the car's momentum: braking, accelerating, etc. But they still don't plug into the ECU. At least that hasn't happened to me yet, and I've been inspected twice. The 2nd time I actually did reset my ECU just before inspection b/c my RT cat keep giving me grief.

DW