First time posting, so may not the greatest at this. I have a 2001 Nissan Maxima Se and have loved it so far, but on Sunday the engine stalled and I got the dreaded P0505 and P0100 combo. P0505 as pending and P0100 as bad, if that matters. So I ordered the OE for them both and plan on replacing them both when I get the parts in, but my main fear is the ECM. I took it out, and no brunt smell and both the bottom and top are clear from any brunt or black marks. In all the videos you can clearly see the damage to the ECM, but I also have yet to read anywhere about a ECM not getting killed by this problem. So is the ECM something that has to be replaced no matter what, or could I have gotten lucky? Also how hard is it to relean the new IACV?

 

I'm assuming we are talking about the IAC and thusly the idle circuit.

Maybe you got lucky maybe you didn't? Do you have a high idle?

I had a high idle and VERY clean ECU. Sent off to a an Ebay "service" seller that i trusted and lo and behold it did have circuilt damage. while waiting i learned that the Throttle Position Sensor and IACV were on the same circuit!

So i bought i OEM TPS and a proper IACV and i got my repaired ECU back. My throttle body didn't NOT have flat surface for the IACV to mount to. I had a skilled mechanic true the mounting surface for IACV before mounting. He also used an addition compound to aid the sealing power of the included o ring type gasket which NOT advised.

I've not had any problems with the throttle circuit since. Why this info in pertant is because of all the ignorant people who replace the same 3 parts several times! The IAC can foul ECU and the TPS and the fouled TPS can fouled the ECU or the IAC and the fouled ECU can fouled the TPS and or IAC.

and that's why it's said to replace both and have the ECU checked out and if needed repaired by a professional.

 

Thankfully I have not put any new parts on, but I didn't think about the TPS, I will have to get a new one before I anything on. Okay, so because I have not put the new parts on, is it a better idea just to order a new ECM from somewhere? I don't want to have the down time of a repair or rebuild of mine, so buying one would be my only choice on that. Also programing have to be done by Nissan or any shop can?

 

some of us get lucky. mine was also spared. if you're auto make sure you unplug the motor mounts

i didn't have to do anything special for the relearn. once it was put back together it was running as it should

 

I heard something about the motor mounts being unpluged, do I just have to leave them unplugged or just to test?

 

No, it's not a great idea to order a new ECM: If you do, you have to reprogram your car keys, and if the car is to run properly, you have to get an ECM with an identical part#, and so on.
As a rule, a bad ECM should not damage your IACV and/or TPS. That is, unless the ECM was severely damaged, damaged to the point where it shorts out the external part. IMHO, that is highly unlikely unless there are burnt tracks and/or melted solder on the ECM board.
At any rate: Read the document about "Preventing ECU Failures" (link in my signature).

 

it's recommended to leave them unplugged, they're known to cause similar damage to the ecu. i believe the proper way to do it is rev above 1000ish before disconnecting so they'll stay in firm mode. mine were replaced with the manual ones a while back so that's another option.

forum member maxiiiboy has put together this document with some more info on ecu failures. you may have come across this already
https://drive.google.com/file/d/0B6O...A3VWlYQVE/view

 

Thank you so much for the guide, that is going to be a huge help. Mine looked nothing like the ones in the pictures, of course that doesn't mean I am 100% good, but maybe at least safe enough to put the new parts on and check it out? If I do have to send it in, is there anything I have to do after I get it back? Reset or Relearn anything?

 

i had no idea about the motor mount(s) i'm sure mine are throughly rotted by now. i know one has an electric motor.