I took my car to nissan to get the key re-programed. Not sure if the immobilizer actually locked up the ecu or not I just new it needed programmed because my security light stays on while cranking and in the on position. Nissan told me the key could not hold the programming, and that everytime they took the key out it lost its programing and they had to start over. They told me they tried several times. I have a 1999 Maxima. It has a new vq35 just swapped with the 3.0 litre ecu and engine harness. Two questions here. Whats wrong with the key, car, ecu, engine harness etc? It is the original engine harness, new ecu out of a running car (because the original fried and wasn't sending a signal to various parts of the motor i replaced it) original key. The second question is am I using the right things with the swap since I have a 99 5spd? 99' 3.0 litre engine harness and ecu. I thought you could use all the same things the car came with when doing a vq35 swap correct?

 

You put the original '99 harness back into the car?

 

Wow, so you changed out everything but the harness? I'd be damned if it wasn't the harness.

 

we replaced itwith a 97' harness and nissan said they dont have the nats wire and they couldnt read the ecu, the ecu just popped up as "error" when they tried reading it. So then we threw the original 99' harness back in the car and and they were able to read the ecu but still couldnt reprogram it

 

the harness opens up the ecu and everything for programing it just wont hold the programing. is that an egine harness issue?

 

That usually means there's a problem with the ECU itself.

 

so i should probably buy a brand new ecu and engine harness to be safe?

 

could the immobilzer or tranponder chip in the key have gone bad? what if i replace those?

 

anyone in the midwest area with a consult 2 or know anyone that has one that wouldnt mind helpping wanna come out and help or have me come out? Or any other suggestions before I go buying a new ecu and key? Not sure what else to check or how to go about checking. They told me maxima engine harness go bad because of certain bends and breaking whch means getting a used one probably has the same damage. My car only has 124,000 miles on it and the harness looks perfect.

 

I doubt the key is the problem if the ECU won't take to programming. Anytime the Consult is used to fix or diagnose an issue they're supposed to give you a printout of either the data or the operation that was performed. You didn't get that huh?



Oh yea the harness going bad is BS. Plain and simple.

 

no, no printout, the tech told me he tried several times and "it" wouldn't hold programng. He never specified what "it" was wither the key or the ecu. When i asked he looked at the service maneger and he looked at the tech and then they both looked at me and the tech said maybe maybe not, chances are if you didnt change the harness its that...then i asked how do harnesses go bad and they said certain bends and fed me BS. But i think the ignition switch and immobilizer are bad. If everytime the tech turns the key back and it lookses programing theres something wrong with the radio wave connection between the ecu and the key...immobilizer...and since its the on, off, accssorie mode obiviously has a problem...ingition switch. Thats what i'm thinking. Sound good?

 

what are the signs of a faulty immobilizer unit? And also are there any symptoms of the ignition switch going out? or when its bad does it just completely go bad? When an ecu fries itself? would the immobilizer unit fry as well since it and th ecu works together sending signals back and forth making sure the car isn't trying to be stolen (another key that doesnt match up)??

 

bumb..can anyone asnwer my last question?

 

The ignition and immobilizer systems are completely seperate.


So the ECU was successfully programmed? There were no errors?

 

yes the ecu was able to be opened for programing. it was programed. There is something wrong with the connection from the ecu to the immobilizer or transponder chip in the key. after it is programmed it either looses programing or the code in the key does not match which puts the ecu right back into lock mode. this is what the tech told me so it sounds like to me either the transponder chip in the key is bad or the immobilizer and the antenna arent working and wont read the code back to the ecu or key..something like that. is there a way to test the immobilizer?

 

or could their be something wrong with the teft box/system? and is the theft system and immobilizer system the same thing?

 

Adrien did you ever figure out the problem? Was it your keys? ECU? Connection? Anti theft module?

My car started one morning then died. Started it 3 times and died three times. Now it won't start.

My mechanic thinks it is the key and security system? I don't know.

We replaced ECU and that didn't fix the prob.

Reprogrammed and all that stuff? Anyway if you got yours fixed please let me know what was wrong.

Your input is much appreciated.

Oh yeah, car starts sometimes but not very often. Still sitting in the shop right now. thx.

 

my max has a very similar problem.. when i go to start it in the mornings it doesn't start ( doesn't even crank ) and so i step outside, hit the lock button, then unlock it, and then start it and it'll start right up. Also, once when I started my car the security light was solid red.. and I didn't want to drive it like that I turned it off and started it up without the light on.

This seems to be a very intermittent problem for me and happens about 10% of the time... I called the dealer he said he'll look at it for 120.. I also called a locksmith he said he can make me a new key for 85 bucks. I'm not sure what to do, will a new reprogrammed key fix this problem?

 

I am having the EXACT same issue with my 99 I30. Maybe 1/20 times the security light stays solid. If I wait 10 mins, I can usually start it--once the light goes out. Once I was able to start it, with the security light on, and drive it home. I tried new ecu--and had the key re-married at nissan, new immobilizer box, same issues. Lock/unlocking the car has no change. Always solid security light when the issue happens---then it goes away mysteriously--until the next time. SUCKS!