I did check previous posts and did not see any that helped.

So here is the deAl. I have 113,000 miles on my car anc My check engine light has been on for half a year now and has been reset by several mechanics But the light keeps coming on the next day. Along with that, the tcs light comes off and on rendomly as well. The mechanics say that nothing is wrong with my cAr and that all they can think of is that I need a new ECM and that will run a grand plus. The problem is not that it's on but i can't pass smog with the light on. Is there any way to reset the computer? I did find a used ECM online for one hundred dollars but I would need instruction on how to put it in. Also, before buying one I want to make sure that buying a new one I'll turn my light off so I can smog. Ia live in California and their smogs are strict. Any suggestions? I need the help.

Welcome to NICO.

The CEL is returning for a reason and the problem is stored in a code in the ECU. Pull the codes yourself or call your mechanic to find out which code it is that keeps coming back. With an ECU code we can help you get it fixed. Without it it's just guesswork.

Read through the EC section of the FSM starting on about page EC-75 and pull the codes yourself. Or, go to Autozone and they'll pull the codes for free.

Where in CA are you?

http://www.nicoclub.com/FSM/i35/2002/

Hey it's nice to hear back so fast from the club. It was my first post so I didn't really know what to expect. I am in so cal in the Los Angeles/inland empire area. I have had the codes pulled several times, I will have to check some of my records or call my mechanic. It's just weird because other people who have posted ecru problems said that their car shut down but my car had never shut down and has ran very well. I would like to avoid buying a ecu/ECM if possible. I really appreciate your help.

Fixmycar wrote:.....It's just weird because other people who have posted ecru problems said that their car shut down but my car had never shut down and has ran very well. I would like to avoid buying a ecu/ECM if possible....

There's nothing wrong with your ECU so no need to buy a new one. Get the codes and diagnose from there. In CA you're pretty much forced to fix the problem before smog even if the CEL is reset prior to the test. The ECU keeps "stored codes" and the smog tech won't be able to pass you until it's fixed.

So I checked on the DTC that came up and it turns out that there were two. U1000 and U1001. I think they have to do something with the communication line. I am not sure what my mechanic was talking about but he said that my Infiniti has different computers for different areas of the car and he believes there is a problem with my max hazard transmission computer? No clue what that means but he wrote it down for me. When I did have it in though last week to have him check it out he did change my spark plugs and valve cover gaskets. I hope this information helps. I appreciate it like you wouldn't believe! Feel free to email/call me as well if necessary.

Casey TeVault
626-347-2441
[email protected]

I did a Google search last night and wasn't able to come up with a definite cause for your codes. It looks like a lot of Maxi/Nissan owners are in the same boat as you. There is a TSB out for the problem but you've got to pay to read it and I'm not sure it would provide a fix. I did read in a couple of posts that the U1XXX codes may not cause you to fail the smog check so maybe stop by your smog shop and see what they say.

In the meantime do a Google search and read up on the possible causes. It looks like a lot of owners have thrown money at parts with only random success. Coils, spark plugs, MAF cleaning, ECU replacement, bad connections, etc. Sorry I can't be more help.

Awesome catch on the TSB goody!

Here's a link to the TSB. Looks like loosening and tightening some grounds...

https://docs.google.com/fileview?id=0B- ... y=CLrZw5wO

Heath

9 times out of 10 a U1000/1001 is a secondary code. What that signifies is that there was a fraction of a second brake in communication from one of the 2 computer network lines that run throughout the car. A U1000 code signifies the A line and a U1001 is a B line, but those codes are not really worth anything without a direction to go in. In the shop we would look into the ABS and TCM to see what the CAN network status would be and apply that to a chart to see where the communication loss is.

In this case I would suspect a throttle motor before anything, but without a proper diagnosis you are just wagering good money after bad. In the year and a half the light was being ignored it could have caused catastrophic damage to your car. The I35 is known to use some oil and it requires fairly consistent maintenance, what is the service history like?

You will need to bite the bullet on this one and get the car fixed by either a dealer or other qualified specialist.

Hey Steve,

I really appreciate you input. You and the other guys here definitely seem to know you stuff. So are you saying that those codes don't signify that I need a new computer and there is something else in my car making the codes come up? Since the lights have been on I have had it looked at my 3 different mechanics, have had my spark plugs and valve cover gaskets replaced, had a new starter put in, and have had 2 oil changes done. I try to take good care of my car and keep up with maintenance. The mechanics always say that my car runs really well and that nothing seems to be wrong with it.

I would take it to a mechanic but no one seems to know what they are talking about when it comes to this problem. All of them are very well known and accomplished mechanics but it seems like this is an issue that most do deal with very often. So I could take it to a mechanics and pay 1200 grand to get a new computer put in but I dont even know if that will fix my issue. My issue isn't that my car is broken or is having problems running, its that the darn check engine light will not come off. There have been a few times when they were able to erase the code but in the morning it is back on again. Looks like I need a miracle worker here! Help me NICO club!

We are indeed here to help, however there really is not enough to go on with just a U1000 dtc.

It looks like you have some one of the problems the aftermarket dreads. Few people know that some of the engine control sensors like a throttle position sensor can actually cause these types of faults...however there should be another DTC.

What you really need is to make an appointment at a well known Infiniti dealer. It is going to cost you about 1 hours worth of labor to have the car diagnosed but $120 is much better than gamb|ing the health of your car on someones guess.

Maybe that is a good idea. The only codes that keep coming up are the U1000 and U1001 which to my knowledge both have to do with communication. I wish there was another way to diagnose the issue without coughing up 120 dollars but I guess that might be my only issue. So you think if I take it into the Dealer they will absolutely know what the issue is? Do you know if smog check stations fail for the U1000 and U1001 codes? Someone mentioned earlier that some dont.

I agree with you that the dealer might just take your money and only tell you, there is a communication problem. You might want to wait (although I am very reluctant to advise waiting) and go to which ever parts store is near you that scans for free to have a "real" code pulled.

You really might want to get a scanner yourself. Even if you do not plan on or are equipped to fix this yourself having a scanner is a good thing to have nowadays.

http://www.amazon.com/s/ref=nb_sb_ss_i_ ... ii+scanner

There is one for every budget all you want is a simple reader.

I must caution you though if you do get one. DO NOT CLEAR ANYTHING. Sometimes the Freeze frame data associated with the dtc is more important to the diagnosis than the code number.

To answer your last question, yes in most states an illuminated CEL is an immediate disqualifier for emissions certification. That is the exact thing and emissions test is used to detect. There are certain qualifiers that an emission test itself looks for, called System Rediness Test (SRT) having a DTC stored like this you will not be able to set the appropriate qualifiers.