Login  |  Register
Nissanhelp.com - All About Nissan
Do-It-Yourself Maintenance Owners Manuals Recalls/Campaigns Service Bulletins Service Manuals Nissan OBDII Codes Glossary & Acronyms More...
Member's Ride Photos Stock Photo Gallery
Classifieds - For Sale Classifieds - Wanted To Buy Classifieds - Mechanic Wanted Classifieds - Auto Services Search Auto Parts
Register FAQ Social Groups Mark Forums Read
ECU failure Forums > > ECU failure ECU failure
Forgot Password? Join Us!


Altima Nissan Altima Sedan Discussion Forum

Reply
 
Thread Tools Display Modes
  #1  
Old 09-14-2017, 01:29 AM
paulorlo paulorlo is offline
Registered User
2005 Altima Sedan
 
Join Date: Dec 2016
Posts: 21
Default ECU failure

Does any one know what causes a CPU that has been sent out for repair to overheat and fail again upon applying battery terminals and turning key to start position? Is there a part that can damage the CPU?
Reply With Quote
  #2  
Old 09-14-2017, 02:34 PM
smj999smj's Avatar
smj999smj smj999smj is offline
Master Enthusiast
2006 Pathfinder
2003 Frontier King Cab
2003 Frontier KC SVE 4x4
 
Join Date: Jun 2012
Location: Prospect, VA
Posts: 1,785
Default

A short in the one of the circuits can do it, however, finding it can sometimes be difficult. For example, some Nissan VQ35DE engines had the problem of the IACV/AAC valve shorting and damaging the circuit board of the ECU. If the board is again damaged, I would send it back to the company that repaired it and have them identify which circuits or pins are, or, may be related to the part of the ECU circuit board that is damaged. At least then you would have a general area of where to check for the problem on the vehicle.
Reply With Quote
  #3  
Old 09-14-2017, 07:01 PM
paulorlo paulorlo is offline
Registered User
2005 Altima Sedan
 
Join Date: Dec 2016
Posts: 21
Default

Thanks so much for your reply. I just sent the ECU back to the company that repaired it and this is the letter I sent them.
Dear Sir:
I own a 2005 Nissan Altima 2.5L 4 cylinder motor. First time I sent you ECU symptoms were: no fuel injector pulse to #1 cylinder. ECU returned and motor ran fine since March of 2017. Second time I sent you ECU symptoms were: car one morning would crank but not start had worked fine the day before. No check engine light symbol when key turned to the on position / no injector pulse to any of the 4 fuel injectors / no spark to any of the four spark plugs / unable to communicate with computer through the OBDII scanning port (comes back link error) / both cooling fans running with ignition key in the on position car motor cold. (indication ECU has placed motor into the limp mode). Asked technician what could cause the ECU to overheat and damage coil/injector controller and he said to check all grounds and make sure they are clean. So I removed the battery and battery tray and found that the negative ground terminal was corroded free from the motor but still making contact with the car frame and a second grounding strap connecting the motor to the car frame was also disconnected due to corrosion. I replaced both grounding cables with OEM cables. Cleaned another grounding cable that comes out of a wiring harness and attaches to the alternator mounting bracket ( another motor ground). Thought I had solved the over heating problem with the ECU. Installed repaired ECU and as soon as I connected the battery terminals after ECU installation all of the above same symptoms were there when I tried to start the car. It was as if I replaced a blow fuse in a shorter circuit. ( repaired ECU instantly failed again)
No check engine light/no injector pulse/no spark/ radiator fans running/unable to communicate with ECU. So I called and talked to Michael and I asked him what could cause the ECU to fail instantly upon applying battery power to the ECU and he said the ECU on these cars runs a host of items and then overheats. It is a communication problem and he suggested replacing the Intelligent Power Distribution Module or IPDM. That could be what is causing the ECU to overheat and fail. Since I do not like to through money at parts before being sure that part is not working properly I am also returning the IPDM with the ECU .This has been a very frustrating process for me. I do not want to install the ECU for the third time and have it instantly fail again. Thanks for all of your help in this matter in advance.
I know this is a long thread but your suggestion of asking which pin is associated with the part of the ECU board that was damaged is an excellent one. It would narrow down the search area. How much would this kind of issue cost to be traced down by a nissan repair shop? I am not sure I would be able to do this myself without help. Thanks again.
Reply With Quote
  #4  
Old 09-15-2017, 10:45 AM
smj999smj's Avatar
smj999smj smj999smj is offline
Master Enthusiast
2006 Pathfinder
2003 Frontier King Cab
2003 Frontier KC SVE 4x4
 
Join Date: Jun 2012
Location: Prospect, VA
Posts: 1,785
Default

Cost would be hard to determine as you are almost at the mercy of the competence of the technician that is working on the vehicle. Electrical shorts/opens get billed by straight-time labor, meaning the cost to repair with be the shop's labor rate multiplied whatever amount of time it takes the technician to locate and repair the problem. This could be a couple hundred dollars or a couple thousand dollars! Usually, the shop or dealer will get authorization from you for a specific amount of diagnostic time, usually 1 or 2-hours, and at the end of time (if needed) will contact you for more time authorization towards finding and fixing the problem as needed. The benefit of working with a dealer is that they do have tech-support with Nissan engineers (for those that know how and know when to use it) and there is a 12-month/12000 mile warranty with their repairs (but many shops do this, as well). If they are unable to locate the short, their common suggestion is to replace the harness, which is another expensive repair in itself. So, you really have to ask yourself at what point do you continue to invest money in a 12-year old Nissan or get rid of it and move onto something else? That's something only you can answer because you know your financial situation. I'm not trying to talk you into not fixing your car and getting another one, but rough trade-in value is probably around $1000 for a 2005 Altima an clean trade-in value is around $3000 with average mileage. Clean retail might be $1500 more than clean trade-in. So, it may not make sense for somebody to invest $2-3K to repair a car when they could apply that money to something "new" or, at least "newer" and in better condition. Just food for thought, that's all.
Reply With Quote
  #5  
Old 09-15-2017, 11:43 AM
paulorlo paulorlo is offline
Registered User
2005 Altima Sedan
 
Join Date: Dec 2016
Posts: 21
Default

Thank you for all your help. I am hoping the repair company can narrow down the pins that current would flow through to over heat the parts in the computer that are damaged. Then I would need a wiring diagram of that circuit to see what parts are on that circuit that could cause a short or over current reading. Sounds like finding a needle in a hay stack. I agree with you on your analysis of the larger picture. Meanwhile I have placed another car on the road until I can decide what to do with the Altima. When I get the CPU back I will write another thread.
Reply With Quote
  #6  
Old 09-15-2017, 09:28 PM
smj999smj's Avatar
smj999smj smj999smj is offline
Master Enthusiast
2006 Pathfinder
2003 Frontier King Cab
2003 Frontier KC SVE 4x4
 
Join Date: Jun 2012
Location: Prospect, VA
Posts: 1,785
Default

There is probably an "Engine Control" chapter of the factory service manual available for download in the "knowledge base" at this site. Nico Club's site features free and complete factory service manuals available for download at their site.
Reply With Quote
  #7  
Old 09-16-2017, 01:48 AM
paulorlo paulorlo is offline
Registered User
2005 Altima Sedan
 
Join Date: Dec 2016
Posts: 21
Default

Thank you. I wish I had gone to school to learn how to read wiring diagrams.
Reply With Quote
  #8  
Old 09-16-2017, 10:49 AM
smj999smj's Avatar
smj999smj smj999smj is offline
Master Enthusiast
2006 Pathfinder
2003 Frontier King Cab
2003 Frontier KC SVE 4x4
 
Join Date: Jun 2012
Location: Prospect, VA
Posts: 1,785
Default

Quote:
Originally Posted by paulorlo View Post
Thank you. I wish I had gone to school to learn how to read wiring diagrams.
If I remember correctly, that's covered in the FSM, as well, in the "General Information" chapter.
Reply With Quote
  #9  
Old 09-16-2017, 11:43 AM
bennyb53's Avatar
bennyb53 bennyb53 is offline
Moderator
2002 Altima
2002 Altima
 
Join Date: Jan 2011
Location: Hawaii
Posts: 2,100
Default

Talk to the ECU repair tech if they tested the MOSFET. Sometimes a fried mosfet leaves a burnt residue that is a dead giveaway, sometimes not. According to you upon applying power the ECU overheated instantly. It means the gateway is open so that a power surge is fatal to other circuits in the board. I suspect that might be the issue. As "smj999smj" mentioned a failed iac/aac valve can fry the ecm. A while back a Maxima owner replaced the mosfet bought from Radio Shack.
Reply With Quote
  #10  
Old 09-16-2017, 04:57 PM
paulorlo paulorlo is offline
Registered User
2005 Altima Sedan
 
Join Date: Dec 2016
Posts: 21
Default

Is the a way to test iac/aac valve with the CPU out for repair?
Reply With Quote
  #11  
Old 09-16-2017, 07:55 PM
bennyb53's Avatar
bennyb53 bennyb53 is offline
Moderator
2002 Altima
2002 Altima
 
Join Date: Jan 2011
Location: Hawaii
Posts: 2,100
Default

Usually you'll have idle issue. You made no mention of it so I think you're IAC valve is fine. Also it triggers a code. Yes you can test the iac valve without the engine running. You'll need a multi meter with Ohm features. Check out the you tube video.

https://www.youtube.com/watch?v=BYuR...IGz_aGp4Ku_llS
Reply With Quote
  #12  
Old 09-18-2017, 08:19 AM
smj999smj's Avatar
smj999smj smj999smj is offline
Master Enthusiast
2006 Pathfinder
2003 Frontier King Cab
2003 Frontier KC SVE 4x4
 
Join Date: Jun 2012
Location: Prospect, VA
Posts: 1,785
Default

Quote:
Originally Posted by paulorlo View Post
Is the a way to test iac/aac valve with the CPU out for repair?
Should be component test in the FSM and you can also check the circuits. Go to the EC chapter and follow you should find the info in the diagnostics for an IACV-AAC valve trouble code, which I believe is P0505 if my memory serves correct.
Reply With Quote
  #13  
Old 09-18-2017, 12:42 PM
paulorlo paulorlo is offline
Registered User
2005 Altima Sedan
 
Join Date: Dec 2016
Posts: 21
Default

I am waiting to hear back from the company I sent out the ECU and IPDM to.
There must be a short to ground issue in a sensor/ solenoid/ actuator.
Reply With Quote
  #14  
Old 09-18-2017, 05:56 PM
smj999smj's Avatar
smj999smj smj999smj is offline
Master Enthusiast
2006 Pathfinder
2003 Frontier King Cab
2003 Frontier KC SVE 4x4
 
Join Date: Jun 2012
Location: Prospect, VA
Posts: 1,785
Default

It could also be in the wiring harness.
Reply With Quote
  #15  
Old 09-18-2017, 10:34 PM
paulorlo paulorlo is offline
Registered User
2005 Altima Sedan
 
Join Date: Dec 2016
Posts: 21
Default

I have dissected the wiring harness by removing the outer corrugated plastic split tubing which was crumbling because of the temperature fluctuations near the motor. This has allowed me to visually inspect the wires. I am also checking for continuity of these wires and a short to ground with a multi-meter that has a tone indicator so I can hear a tone of conductivity before it is digitally displayed. (love that tone) I will replace the outer plastic jacket with new ones once I am done. I was also thinking that when the repaired computer comes back I could power it up without any of the wiring harness connections attached to their respected motor sensors/ injectors/solenoids etc. Then check for a check engine light going on with turning the key to the on position communication with the CPU and if the cooling fans turn on. Then one by one attach the wiring harness connections and again check for the above. Using the CPU as a very expensive fuse to find the sensor/ short/actuator/solenoid etc that causes the CPU to fail. Just an idea.
Reply With Quote
Reply

Bookmarks

Tags
ecu, failure

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 06:31 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Search Engine Optimisation provided by DragonByte SEO v2.0.42 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.