It's The Computer!

Michael Mobile Technician Utah Posted   Latest  
Discussion
Programming
2000 Nissan Maxima GLE 3.0L (VQ30DE) 4-spd
Idles Low

I had two experiences in the last week that were educational. Two shops had me look at vehicles that were stumping them. One a 2000 Maxima. The complaint was a low idle and IAC codes. Over the phone I suggested that the ECU could be burned by a shorted IAC. The shop told me that both the ECU and IAC were new. The ECU was a reman from the dealer. I went over and used the factory scan tool to attempt a relearn. The idle just never changed. After that I connected a 4 channel scope to the IAC motor leads going to the ECU. No matter where I set the throttle there was no action on the scope. I asked the technician about the wiring. He assured me there were no shorts and no opens. He told me he saw activity on his meter that told him the drivers were working. I moved the scope and leads to the inside of the car and connected at the ECU. Every once in a while I could see one driver move. Even though it did not seem likely, the logical explanation was the ECU was defective. Since I was not certain, I suggested a used one from the wrecking yard. It came in today. I programmed keys and started the vehicle. Now normal revving when warming up. Relearn went through like a champ.

The second was a 2012 Acura MDX. The vehicle had both P0300 and individual cylinder codes. The vehicle ran smooth for about 30 seconds then would run on 3 cylinders. In looking at the wiring diagram, I could see no commonalities. After shutting off the engine, the vehicle would start and run great again for 15 seconds then change to 3 cylinders. I checked the coils and they were all signaling normally. So the problem was the injectors dropping out. The injectors are buried on this model. Since the issue did not cause any circuit codes I decided it was in fact the ECU that had failed. The replacement came in today. I went over and adapted the computer. It now runs fine.

As a mobile programmer I get to program many computers and components that are not defective. Sometimes I laugh inside when I hear the reasons why the computers are replaced. In some cases the techs are right. As crazy as the explanation sounds, it fixes the problem. When I diagnosed the Acura, I went in and said "Its the computer", yeah Mike, sure it is. We went with the second hand part knowing it was a gamble.

I had one more this past week that I condemned the ECU on. We will see how that one goes. Maybe 3 for 3!

-Mike

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Justin Mobile Technician
Utah
Justin Default
 

Your first one I have seen. I ended up with a visual inspection of the ECU board. It’s 4 easy screws on both sides. On mine the IAC driver and all the way across the board had a dramatic thermal event. With the brand new IAC from the dealer already tried after an aftermarket one was tried, it was an easy call to get the ECM. I had one today that was a 2007 Dodge 3.7 Dakota. Program this new…

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Reid Owner/Technician
New Jersey
Reid Default
 

I find it to be a nerve wracking experience at times trying to tell a shop owner that the vehicle he called me in to program still has a problem after I programmed it. Last week a customer called me to program a 2014 Jeep. He had installed a reman ECM along with a new alternator to solve a charging system issue. Programming went fine, engine ran fine, charging system operated correctly but set a…

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Justin Mobile Technician
Utah
Justin Default
 

I typically get too busy for a shop whos owner gives me the temper tantrum when I‘m there. I treat my customers with professional respect and expect the same in return. Those that use me this second way end up being very respectful . I would rather a couple jobs for the nice guys that aren’t on my level that pay and respect my services than any time spent on one that doesn’t. Let the jerks have…

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Allan Instructor
Manitoba
Allan Default
 

Reid you are called in to perform a service, program a module, if you perform the service and it doesn’t correct the customers problem well, you didn’t diagnose the problem, or mis-diagnose it, they did. Their mis-diagnosis has nothing to do with you. it’s not your monkey. If they also want to pay you to diagnose the problem that’s an option. You performed a service, get paid for that service…

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Victor Technician
California
Victor Default
   

Talking about Nissan from 2000, everytime the IAC doesn't turn on it is all about the ECM. Replace the Mosfets. 15 min job. ( NO DRAMA) There are a pair of Mosfet (STA5509A) in array internally in the ecm one power up the second one both are the same component, we stock them specially for Nissan form those days. One thing that able or actived the Mosfet is Thermostat signal. So checking the…

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Miguel Technician
Tennessee
Miguel Default
 

Thanks man

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Samuel Technician
New Jersey
Samuel Default
 

Never replaced these....any programming required afterwards and it the replacement as simple as it sounds?

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Raymundo Mechanic
California
Raymundo Default
   

Victor Alvarado How can I contact you for classes or any training you may offer.

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Victor Technician
California
Victor Default
 

Raymond do you speak spanish ? Send me a Private message. If you do...

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Miguel Technician
Tennessee
Miguel Default
 

Hey Victor I'm interested too if you offer training

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Victor Technician
California
Victor Default
 

Publica tu email aquí Miguel.

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Miguel Technician
Tennessee
Miguel Default
 

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Marcos Diagnostician
Arizona
Marcos Default
 

I’m interested if you offer training as well

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Victor Technician
California
Victor Default
 

Post you email here.

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Marcos Diagnostician
Arizona
Marcos Default
 

… Gracias!

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Victor Technician
California
Victor Default
 

Publica tu email aquí Ray...

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Raymundo Mechanic
California
Raymundo Default
 

… Saludos.

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Victor Technician
California
Victor Default
 

Super

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Stanislav Manager
Russian Federation
Stanislav Default
 

Before doing this, I would prefer to simply disconnect and reset the battery. Very often it helps.

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Shane Technician
Massachusetts
Shane Default
 

I've had 2 different hondas do the same thing, shutdown injectors after 15s of running. If you do a crank pattern clear and relearn the problem goes away for about a month. A pcm fixed both of them

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Victor Technician
California
Victor Default
   

Yes it is the pcm... but, What is wrong inside the pcm? This is the case. Honda and Acura comes with 2 different alternators and both report diferent to pcm. So since this post doesn't give you that info it is hard to say what was actually happening then shutguning the pcm is the next step. (...and fortunally it is always the solution) If tech check the voltage the pcm is reading using the…

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Greg Technician
Colorado
Greg Default
 

Very helpful, Victor! Where do you source your electronic components?

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Victor Technician
California
Victor Default
   

Hello, we outsource that throu out Alibaba companies. Some comes from Italy for our bmw, Volvo, and audi repairs (Infineon electronics "Alliedelec dot com") Also in Central America still has those kind of RadioShack stores. Remember those from the 90s here in the USA... I missed RadioShack... saludos.

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Oscar Diagnostician
Virginia
Oscar Default
 

Michael you seem to have all the answers for this problematic cars. I have a presently have a problem car my self, maybe you can give me some tips. 2015 Nissan Rogue, custumer tells me that the vehicle was stolen with the key. Now he bought one smart key at the dealer and would like to get it program, I’m thinking no big deal. start the process with consult3, goes through the process, when…

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Michael Mobile Technician
Utah
Michael Default
 

There are some of these that the BCM burns when attempting learning all keys lost. Here are three BCM numbers that are almost certain to fail. 284B1-4BA0A, 284B1-4BA0B, 284B1-4BY1A The solution is to replace the BCM if one of these matches. I have personally not experienced that model before but there is chatter on other forums about fails.

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Oscar Diagnostician
Virginia
Oscar Default
 

Thanks Mike, I saw the message on my Xtool, but the part number did not match any of the numbers that was given on the message. But I do think that I have a bad BCM I will keep you posted what I find!

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Geoff Diagnostician
Hawaii
Geoff Default
 

Mike, in regards to; "Since the issue did not cause any circuit codes I decided it was in fact the ECU that had failed." Do you take that gamble often, or just on newer stuff, or model by model, or...? With the older beat-up garbage I deal with, DTC have a 20% relevance factor, I estimate.

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Michael Mobile Technician
Utah
Michael Default
 

Geoff, In this case the behavior did not make any sense. Why did a restart make it run better for 15 seconds? This is why my gut was telling me that the problem had to be in the PCM. The used module was $150. I proposed the gamble to the shop owner and he concurred with my logic. The cost of the replacement module often plays a role in the gamble whether the vehicle is new or old, junk or…

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Geoff Diagnostician
Hawaii
Geoff Default
 

Got it! Thanks. Also....morbidly curious....2000 Nissan Maxima and "I went over and used the factory scan tool".....do you have a Consult 2? They are rare beasts (and completely unnecessary, I'm told) but old stuff is cool. :-)

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Michael Mobile Technician
Utah
Michael Default
 

Geoff, I used the consult 3. It was backward compatible to this model.

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John Owner
New York
John Default
 

Geoff, I regularly use my Consult 2 almost weekly. There are some functions particularly NATS 2.0 programming that Consult 2 works much better than Consult 3 Plus. I am one of those that has Consult 2, Consult 3, and Consult 3 Plus. I can attest that Consult 3 is a tool that I have almost put into orbit on multiple occasions. Again, there are functions that Consult 3 is better than Consult 3…

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Geoff Diagnostician
Hawaii
Geoff Default
 

Great info JR! As someone who never does anything with NATS or configuration of any module, if I would have picked one (C-II) up in the dealer closure sell-offs, I think I still would have never needed it. I was constantly frustrated with S.O. stuff on Asian many years ago and ended-up getting a G-Scan, before most people had heard of it. I really love that tool. It's good to know somebody…

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