I have an 03 350z Track, I just purchased a Cobb AccessPort yesterday, did all the updates and loaded on the maps before I installed it in my car. I did the install and reflashed my ecu with stage 2+ map. Everything went through smoothly so i took the car for a spin and it was driving great and pulling a bit harder than before.

With that being said, I came to a stop and realized that the car was idling rough and it would drop in RPM to about 450 then climb back up to 700 SLOWLY then eventually drop again after a few seconds. There is no Check engine light but I still ran a scan on the ecu and came up with the code "P0605" which is ECM malufunction I believe.

I decided to load the stock map back in the car and completely uninstall the AccessPort as well as do a hard reset and disconnect the battery over night. I reconnected it back up this morning and started the car and it started doing the same thing again and throwing the same code "P0605"

The car idled PERFECT before the Cobb AccessPort install so I dont know what happened and I hope AccessPort did not damage my ECU. Please chime in and try to help me out with this issue


-Sam

 

I would recommend contacting Cobb and see if they are willing to help. I believe UpRev had a way of fixing brain dead ECMs from bad flashes, but you had to send them your ECM.

My FSM for my G35 indicates doing a reset (as you did), and if the code comes back, replace the ECM. Perhaps the flash memory is damaged - sorry.

 

I tried contacting them and they said that the ECU needs time to relearn itself. I drove the car for about an hour and put 40 to 50 miles on it so I think that was more than enough time.. I really dont wanna have to replace my ECM because AccessPort Damaged it...

 

The ECU error is common when you reflash these ECUs, but you should be able to clear it by disconnecting the battery. The rough idle may be from clearing the long term learned fuel trims, so driving it should clear that up. I would reinstall the AccessPORT, then, disconnect the battery, then drive the car. If the code pops up again, just disconnect the battery and see if that dosent clear it up.

Travis
COBB Tuning

 

I have already tried everything you stated above. The code still comes back and the car drops to 450 rpm in idle.

 

sounds like the 02 compensation is swinging too much, ie the tune isnt very good for your car.

 

I went back to STOCK tune and uninstalled AccessPort and it was Still doing the same thing.

 

Zorgazm,

Here is the error code.
http://www.nissanhelp.com/diy/obd_codes/p0605.htm
you are correct it is a ECM code.

Now have you tried to do a ECM reset? (Attached)

C

 

Try the stage 1?

 

All the above did not help

 

I recommend following what travis from Cobb has told you to do. If the problem then remains they have been well aware of issue and your actions taken.

Sometimes the ECU will take longer than 40-50 miles to relearn. The ECU is not only needing miles but cycles ( driving then parking then restarting and driving) to learn things like idle.

I could say more, but, just do what Cobb tells you to do.

 

If uninstalling the AccessPORT did not fix the issue, then you have a mechanical issue. Did you install new intakes or anything like that concurrent with your AP install. Did you install new exhaust parts or anything like that?

 

i noticed the same problem when i installed mine... but no engine code came up, what i did was just rasied the rpms 150+ so it idles at 850........ after i did that it was fine...


but i also noticed that if i shut my car off then shortly after turn it on.. the idle would drop really low, but climb bac up to normal..


besides that no complaints, cant wait to see what it does for me on the track..

 

UPDATE: WOW now its throwing another code "Random Misfire"

I installed nothing new..My car was idling and driving perfect before the Cobb Accessport was installed.

 

The random misfire is likely related to the low idle.

Since Cobb is checking your thread, you should ask if you could raise the idle to see if that helps.
Like the other poster did, but ask first.

 

Raise your idle. I had to bump mine about 150 rpm to get it back to 750. I'd be willing to bet that is your only problem. Any car that I've ever driven acts like that when the idle is set too low. It goes to the low end and then raises to keep from dying. I'd be willing to bet money (not much ) that this will solve your issue.

 

My next suggestion was to contact Cobb, but they are already on it. Let me know how I can help. My car had an O2 sensor issue when the Cobb was installed, but it still ran fine (Ran the AP for almost two years with no problems). I never experienced any idle problems AT ALL, nor did I ever through a random misfire code. I DID get the ECM error every once in awhile. I thought it was caused by the O2 sensor issue I had, but maybe the AP was the cause?

 

and another thread about cobb accessport...not so good...maybe it has something to do with flashing the ecu a million times for every change made and it messed ur ecu up and now u need to buy another ecu which is not cheap..good luck op...

 

just so happens I have an '06 base 6mt ECU in my bedroom right now.... to bad you have a DE

 

Reflashing the ECU will not cause ECU damage. Either your ECU is working or it will just die, there isn't any inbetween really. I would check your o2 sensor reading, if that appears to be functioning properly, increasing your idle by 150rpm might be the fix you need. When you reflash the ECU all the learned fuel trims are erased, so that might be part of the issue as well. You can also try cleaning your MAF sensor.

Even with the AccessPORT uninstalled your car is idling poorly, it isn't an AccessPORT issue since the car would once again have a completely stock ECU. That means that something mechanical is causing your car to stumble at idle. My guess is you have some form of small vacuum leak or something of that nature.

How does the car behave when you are driving it?

Travis
COBB Tuning