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I gave up on the original ECM as replacing the burnt chip as tracing and fixing the broken paths did not fix the issue for me.
I bought a used 3T ECM on eBay (120.00). I bought a used TB (included the IAC) for 23.00 bucks at the local pickyourpart. It was off a 2000 Maxima and looked to be in newish shape. My car is a 2001 Infiniti I30t. The only difference I saw was a valve sitting on top of the TB. I unbolted it and closed off the small tube that went to the TB. I also got a new TB gasket from the dealer for like ~5 bucks.
The next issue to tackle was the programming of the key and IAC learning process. I called the closest Nissan dealer and they said they would not program my key because my car was not a Nissan (whatever). The Infiniti dealer was just too far and tow would be too expensive!
That's when I started searching for a OBD software that could potentially perform the key programming. I ran into the Nissan Data Scan II for Windows. After some researching, I decided to buy it for 69.99. I purchased a cheap OBDII scanner for under 10 bucks on eBay as well. I dusted off an old lap top running Windows XP and installed the software.
The key programming literally took 10 seconds. I used the master pin that appears to be in many places online.
The car started right up!! I let it warm up for a few minutes and even drove it around the block a few times. The idle was still high but I had not performed the IAC learning yet. The software also can do this. I followed the instructions for this and voila...idling leveled off at ~700 RPMs. The car runs so smooth now!! Finally!!!!! I have been driving the car for the past week days with no issues.
BTW, I also disconnected the motor mounts, performed the TB coolant bypass and replaced the 15 amp fuse (#58) with a 7.5 one.
A sincere thanks to all of you for helping out with this thread. If you are in the San Diego CA area let me know and you can use my laptop with the NDS software and OBDII plug.
Hmm. My car has similar problems. The p0430 is a common problem
My car has the p0430 code and my alternator is also bad. Been fine for about 4000 miles though, just killed a battery.
Nothing to do with it. Thats an o2 sensor or cat coverter.
Originally Posted by 20thAnn
Haven't pored over this thread, but have you checked into the active motor mount issues these Maximas have? It's hard to believe, but Nissan's attempts to make your engine purr quietly might have caused a major ECM malfunction. I just BARELY got mine replaced under the 80/8 warranty. They unhooked active engine mounts, replaced IACV (on my dime), then later found out the ECM was fried and replaced it.
Dammit dude you stole my thunder...I was gonna be the smart guy.
When my motor mounts were shot i replaced with a manual set even though I have an auto. Bit more of a "sporty" vibration from the engine...but its not going anywhere..and no frying anything either.
I have a 2001 maxima Se I replaced the ivac had coolant in the ivac I tried to relearn the idle but the consult cant get the car to relearn idle my idle is really low I have to hold on to the gas pedal if not the car dies. Anyone have any suggestions?? Could it be the ecm? It's my daily driver so any advice will help thanks
I have a 2001 maxima Se I replaced the ivac had coolant in the ivac I tried to relearn the idle but the consult cant get the car to relearn idle my idle is really low I have to hold on to the gas pedal if not the car dies. Anyone have any suggestions?? Could it be the ecm? It's my daily driver so any advice will help thanks
Have you took the time to read this thread or nah?
I have benefited a lot from the information posted on this forum. For the benefit of new owners, I have put together a short note on how to prevent ECU failures in our cars: https://drive.google.com/file/d/0B6O...ew?usp=sharing
Edit 9/1/2018: Replaced link with a link to an updated v4 of the document.
I have benefited a lot from the information posted on this forum. For the benefit of new owners, I have put together a short note on how to prevent ECU failures in our cars: https://drive.google.com/file/d/0B6O...ew?usp=sharing
Thanks a bunch for the great write-up! I've done the coolant bypass when replaced my IACV a couple of months ago, no fried ECU/ECM, idle is perfect again. Safe-keeping this PDF in my Max files
One question. Have you tested the 10 amp fuse? I have a few of these as spares but not the 7.5.
Thanks a bunch for the great write-up! I've done the coolant bypass when replaced my IACV a couple of months ago, no fried ECU/ECM, idle is perfect again. Safe-keeping this PDF in my Max files
One question. Have you tested the 10 amp fuse? I have a few of these as spares but not the 7.5.
No need to test the 10A fuse. It's guaranteed to work, but it will NOT protect your ECU as well as the 7.5A fuse. With 10A, there is some danger that the ECU will be damaged before the fuse blows. So, get a 7.5A fuse (and a couple of spares) - it's only a few pennies.
First off a big thank you for all the info you are providing in this great thread.
I have a Nissan Almera, a model found in the European market, which comes with the QG15DE engine. As I see from the photos, the engine is pretty much the same with the one in Maxima.
Now a few years back the engine stopped running, I went searching for the problem in more than 10 repair shops, and unfortunately it all concluded to a faulty ECM. Changing ECM was not an option as it costs 1000 euros, so I had to improvise. I found a technician who figured out that my idle sensor is malfunctioning and he simply unplugged the harness. The result was a running engine, without the ability to maintain RPMs. For 5 years now I am manually keeping the RPMs steady using my right foot…even when I brake.
Recently I stumbled upon a Greek forum (I am from Greece) and there was this guy explaining how this exact problem can be fixed. To make the long story short, I discovered that my idle sensor was fried and so was an STA509A chip located in my ECM. My car doesn’t have electric mounts, so I assume it may have shorted due to coolant leakage.
I ordered a pack of 10 STA509As from Aliexpress and 1 idle sensor all for 60 euros. Nissan asks 300 euros only for the idle sensor. I am planning to replace the fried parts, connect the harness back on the idle sensor, calibrate the motor and see what happens.
Here comes the problem. The STA509A has 10 pins. Pins 1 & 10 are the sources (S), 2,4,6,8 are the gates/input (G) and 3,5,7,9 are the drains/exits (D). My STA509A was burnt at the 3rd and 5th pins and there is no continuity from the STA509A to the corresponding pins of the ECM. My thought is to connect the 3rd and 5th pins with the corresponding exit pins using a thin cable, but I am not sure if these two pins are sending signal to anything else on the circuit board.
I would really really really appreciate if someone could provide me with the schematics of the ECM so I could figure out what to connect and how to fix it. All I am missing to put an end to my problem is the schematics of the ECM which unfortunately I couldn’t find anywhere over the internet.
Is there anybody who can help me out?
Perhaps Kaane, since you experimented with the fuses, maybe you got the schematics?
While I do not have a schematic for the ECU, I am fairly certain that the Drain pins of the chip (pins 3 5 7 9) are dedicated to one specific circuit and not doing double duty.
Using your Before Repair photo, if you look closely at pins 3 and 5, you can see that they connected to a square pad immediately to their left. (btw, you have pins 3 and 5 mislabeled.) If you look at pins 7 and 9, they also connect to a square pad, although pin 9 goes to the right. Theses square pads are resistors.
In the After Repair photo, pin 3 is not connected to anything. The traces have come off the printed circuit board. Even the square pad for the resistor is gone as well as the one right beside it. Pin 5 seems to be connected to the square pad, but the resistor immediately below the square pad looks to be damaged.
I don't know if the resistors are being used in series in the circuit, but it would explain why you do not have continuity between the STA509 pin and the ECU pin.
If the resistors are wired in series and you run a wire from the STA509 pin to the ECU connector, this may allow more current to flow. More current flowing could cause the chip to fail prematurely. But I'm guessing here.
Do you have any way to get another ECU and inspect/examine it. I think that would tell you a lot.
Thank you for your message DennisMik, I really appreciate it.
It seems to me as well that pins 3 5 7 9 are dedicated to one specific circuit but the schematics is to make it 100% sure, and not risk burning something up.
Using my “Before Repair” photo, you are absolutely right that I mislabeled pins 3 and 5, sorry about that. Now, in that photo, if you look closely you will notice that pins 3 5 7 and 9 are all connected to these square pads on their left. None of these pins goes right. Moreover only pin 7 appears to be the only one connected with resistors. The rest square pads, since they are not connected to any resistors, what are they for? Are they used as “stand-bys” or something?
In the After Repair photo, you are right that pin 3 is not connected since the traces have come off. Pin 5, even though it appears to be connected, it is not, as traces have come off as well, but from the upper side of the board. Lack of continuity between pin 5 and ECU pin 16 confirmed it.
Resistors located on the left of pin 7 are working as continuity exists between pin 7 and pin 6 of the ECU. (Voltage is to be measured)
Pin 7 goes to ECU pin 6 – continuity ok Pin 9 goes to ECU pin 15 – continuity ok Pin 3 goes to ECU pin 7 – no continuity Pin 5 goes to ECU pin 16– no continuity
The schematics will confirm that pins 3 and 5 go only and directly to the ECU pins 7 and 16 respectively, where I will connect them with a small cable and restore continuity.
Unfortunately I cannot get my hands on a similar ECU and this makes it even more difficult for me.
My comment about pin 9 connecting to a pad on the right is due to my inability to master the complex task of counting to 10. Sorry.
Those seemingly empty pads may be what you suggested, a spot where a resistor could be added. It is possible that they could be used as a pass through to get to the other side of the printed circuit board, but your After Repair photo doesn't show any hole in the center that would have to be there for a pass through.
If a resistor was supposed to be in the circuit, you could measure resistance from the ECU pin to the STA509 pin, measuring resistance for pins 7 and 9 as a reference.
i checked for shorts and continuity on the harness and can't find any issues. IACV has 22ohm's between coils. So why the hell would the ecu fry? What else could cause this?
I AM HAVING THE SAME ISSUE ONLY I NOW KNOW THE ECM AND THE IACV HAVE TO REPLACED AT THE SAME EXACT TIME. THIS IS MY SECOND IACV AND ECM. I ALSO LEARNED IT DEPENDS ON IF THE IACV IS OEM PART.
Harness has no shorts, I removed the whole thing and checked it. I did ran into something interesting, there is a company that fixes these ecu's and they claim that a bad Throttle position sensor can cause the ecu to get fried. I asked them how it's possible but they didn't answer. They also said that running a new IACV with fried ecu will just damage the IACV again. I tested the IACV valve and i am getting around 24-25ohm between the terminals. The manual says 22ohm's, could the IACV be fried again?
IM HAVING TO REPLACE BOTH THE ECM AND IACV AGAIN ...DUE TO NOT REPLACING THEM BOTH AT THE SAME TIME.
I AM HAVING THE SAME ISSUE ONLY I NOW KNOW THE ECM AND THE IACV HAVE TO REPLACED AT THE SAME EXACT TIME. THIS IS MY SECOND IACV AND ECM. I ALSO LEARNED IT DEPENDS ON IF THE IACV IS OEM PART.
The fact that the ECU and the IACV need to be replaced at the same time has been documented in post #206 above (which refers to this note: https://drive.google.com/file/d/0B6O...1fNlF5QjQ/view ). The note also mentions that TPS is another suspect; and yes, we don't yet understand how the TPS can damage the ECU. If you do, let me know - I would update the note accordingly.
The fact that the ECU and the IACV need to be replaced at the same time has been documented in post #206 above (which refers to this note: https://drive.google.com/file/d/0B6O...1fNlF5QjQ/view ). The note also mentions that TPS is another suspect; and yes, we don't yet understand how the TPS can damage the ECU. If you do, let me know - I would update the note accordingly.
I have replaced at the same time but still idling and running poorly. Not to mention...now I have P0110 code, a few fuses keep going bad and when I turn the headlights on the dash lights go off ...strange.
Any suggestions or advice would be very appreciated and helpful.
I have replaced at the same time but still idling and running poorly. Not to mention...now I have P0110 code, a few fuses keep going bad and when I turn the headlights on the dash lights go off ...strange.
Any suggestions or advice would be very appreciated and helpful.
I have replaced at the same time but still idling and running poorly. Not to mention...now I have P0110 code, a few fuses keep going bad and when I turn the headlights on the dash lights go off ...strange.
Any suggestions or advice would be very appreciated and helpful.
P0110 points to a problem with your Intake Air Temperature Sensor. Also, find out which fuses are blowing, and why, and fix the underlying problems. You'll need the FSM for your car; you can download it from here: http://boredmder.com/FSMs/Nissan/Maxima/ .
I am newbie here. So I appreciate any comments positive or negative. I am trying to learn about my maxima and the comments here have been helpful. I am grateful to all for any info that you have provided. I am learning a great deal and feeling more confident about understanding this car.
I have a 2001 Maxima Se 10th anniversary edition ( automatic, with tcs). I purchased it used from a neighbor 7 years ago. It has been running very well.
The car has 94k miles on it. It has started giving me the dreaded P0505 error code. This has been ongoing for about a month. The car starts without issue, its idle rev are higher than the normal 750 ( appox 800-900 in P or N). But other than that it seems to be working fine. I dont really push the vehicle but it does rev about 3000 without an issue. Also I do not think that the ecu is blown b/c I do not have any of the other symptoms related with a problem ecu ( starts fine, no smells, revs are good).I have not physically take the ecu out and examined the chips and boards.
My question is: if the p0505 error is thrown, should I try the precautions mentioned in maxiiboy's excellent write up ( many thanks for that note maxiiboy and nakis) on the p0505 error? My thoughts are that if the precautions outline in the note are taken I may be able to change just the iacv valve and save myself doing the ecu dance. Or am i just kidding myself?
Even if the ECU is damaged, you can install a new IACV and not have to worry about damaging it. The damage inside the ECU is like a fuse is blown. There will not be any electricity going to the IACV. It simply won't work. You will have the same symptoms as before you replaced it.
It would be pretty rare for the IACV to fail without causing the ECU to burn up the STA509 transistor chip, so I think you will probably have to get the ECU repaired.
my iacv failed and ecu was spared, the easiest way to check it is to pull out the computer and take a look. it shouldnt take too long, you'll need a small 90 deg screwdriver or ratchet
I am sorry for jumping on this thread, but I am new to this forum and can't post my own thread, yet. I just experienced a problem that I am trying to get some help so that I can better understand it.
I have 2001 Maxima SE 20th Anniversary (5 speed) with ~135K miles. For the most part it has been a smooth ride, with one exception and that is emissions.
- 55K I got a P0420 (Catalyst System Efficiency Below Threshold Bank 1). I took it to the dealer and they re-programmed my ECU. I was told that there was a re-call on my car and the emissions thresholds had to be updated. Problem solved.
- 110K I got a P0430 (Catalyst System Efficiency Below Threshold Bank 2). First mechanic wanted to replace my catalytic converter. Second opinion resulted in just replacing one of four oxygen sensors. I didn't capture which one it was, but I am guessing it's the one that controls Bank 2.
- 113K I got stranded on the road once because I lost power. After a tow back to my house, the car started fine the next day. I took it to a mechanic and he tested electrical system, but could not find anything wrong. So continued driving until I got stranded again and this time it was clearly an alternator.
- 115K another Oxygen Sensor (13374).
- 124K power steering high pressure hose.
So here is the fun part. I get another P0430. Two different mechanics tell me that I need a new catalytic converter and Oxygen Senor(s). Day before I take in for repair, I decide to reset my computer by unplugging the battery for about 15 minutes. Plug it back and Check Engine light is still on. Oh well, I take it to the mechanic. He calls me couple of hours later to tell me that the code is no longer P0430, but instead it points to an Oxygen Sensor that controls Bank 2. I told him that I tried resetting the codes with the battery and maybe it'll take some time for P0430 to come back. So we decide to just do O2 sensor for now. I get that done and while driving home from the mechanic (~ 5 miles) my car stalls. I tried starting it, but it just won't hold the idle. I also smelled an electrical fire inside the car. I towed it back to the mechanic and he told me that my Idle Air Control (IAC) valve shorted and fried my ECM.
Couple of questions here:
- Is there any way a new O2 could short my IAC or this just a freaky coincidence?
- Why do I seem to have electrical problem around the same time my O2 sensors are being replaced?
- How common are these problem in 5th Generation?
I love driving this car, but I am almost at the end of the road here. Please help!!!
I don't mean to bump this old thread; however, when you replace O2sensors don't you update the ECU with an ECU ID code? Could not updating the ECU have created the damage? When they replaced the O2 sensor did they update the ECU?
Last edited by maximatech12; 05-09-2016 at 02:36 PM.
Does anybody have the exact trace diagram handy? I see at least a few traces that will have to be jumpered, and I'm having trouble finding one. Thanks in advance!
From Nakis first page post, he gives these
ECU pin 6 to STA509A pin 9
ECU pin 8 to STA509A pin 3
ECU pin 7 to STA509A pin 7
ECU pin 17 to STA509A pin 5
I'm trying to figure out the traces to the other 6 pins.
Does anybody have the exact trace diagram handy? I see at least a few traces that will have to be jumpered, and I'm having trouble finding one. Thanks in advance!
What you are asking for is the Circuit Diagram of the ECU PCB (PCB stands for Printed Circuit Board). I am pretty sure this diagram is not available to us, or to anybody else outside Nissan; I would love to have it, but I am pretty sure it's a Nissan proprietary thing.
What you are asking for is the Circuit Diagram of the ECU PCB (PCB stands for Printed Circuit Board). I am pretty sure this diagram is not available to us, or to anybody else outside Nissan; I would love to have it, but I am pretty sure it's a Nissan proprietary thing.
What I was looking for was what pins on the STA509A goes to what points on the ECU circuit board (ie. Connector). My traces were burnt so there was no clear path.
Hello all,
The big chip with the red arrow in my Maxima2000Auto burnt, probably even sparked because inside the top cover, there is a black/brown spot the size a penny of smoke/fire.
Of the 3 chips in the photo, what do you think what caused mine (I taped it) to burn ?
Thank you so much.
Thanks. burnt ECU back in the car (needed the car to move).
Will have to go to Junk yard.
2 urgent Questions related to ECU
1) Are 2003=2002=2001=2000 (mine=2000 Auto)
2) Are 2003/2/1 Standard Transmission = 2000 Auto ?
Thank you everyone.
No, they are not the same. You have to obtain an ECU with the same product number. Alternately, you can fix yours - and avoid the problem of key programming. Read the document about ECU failures (link in my signature). And even more important - you have to fix the underlying problem first, before fixing/replacing the ECU.
Hello all,
The big chip with the red arrow in my Maxima2000Auto burnt, probably even sparked because inside the top cover, there is a black/brown spot the size a penny of smoke/fire.
Of the 3 chips in the photo, what do you think what caused mine (I taped it) to burn ?
Thank you so much.
Did you ever get an answer to this question? I have the same component smoked in my ECU and also have an automatic 2001 Maxima. I suspect it's from the motor mounts so I plan to disconnect them. Do I need to also repair the ECU or is this component only for that purpose so no longer used if motor mounts are disconnected?
I'm really having trouble disconnecting the engine mount connections.
Please advise. Don't want to break anything
Not sure what connector type it is, but oftentimes I use a small screwdriver to help press down on the release tab since they like to get stuck. Alternatively, you could just cut the wire(s), as long as you tape/seal them off it will have the exact same effect as disconnecting from the mount. It wont be of use to you nor anybody else in the future so I dont see the point in keeping it intact.
Another confirmed user where motor mounts fried ecu
Originally Posted by 2K2Beast
TO EVERYONE WHO HAS HAD A SHORTED ECU IN CONJUNCTION WITH SOME SORT OF IACV PROBLEM:
My friend 1phatmax had the same issue, and both (2!!!) times he bought an ecu it was from a dealer who should have known this.......if you have an automatic then you have electrical motor mounts.
Your motor mounts are MOST likely gone bad, shorting out your IACV and/or ECU....
only if someone had sued Nissan would have put out a recall or TSB for this isssue........
EDIT: Its most likely your Front/Back mounts and not the Right/Left mounts
First off thanks to you and the earlier commenter who mentioned it was likely the motor mounts. I have an 01 Auto GLE. First the idle was too slow to the point the engine would stall. Replaced the IAC and cleaned the throttle body. The idle would then surge when in park. Took it to Nissan. They said throttle body was shorted out and ecm needed to be replaced. Replaced throttle body even though I knew it didn’t seem right. Nothing changed. Then I came upon this thread. Took out ecm and saw it was partially melted. Unplugged motor mounts while rpm was around 3000. Ordered a remanufactured ecm off eBay with exact part number. Took it to Nissan to get programmed. Now car runs beautifully. This issue ended up costing me many hundreds more than it could’ve if I had seen this thread earlier but I’m glad it is over with. Thanks again to you and the previous poster. I probably wouldn’t have ever figured this out without y’all and prob would’ve taken a sledgehammer to my car.
Well, searching this thread is a Herculean task. I just tried to find one of my earlier posts so that I could update a link therein. I failed .....
So, the reason I am here: With the time elapsed, the effect of IACV Failures vs. the effect of Engine Mount Failures became much more clear to me. I have updated my earlier note accordingly. If you are interested, read it here: https://drive.google.com/file/d/1Npo...ew?usp=sharing
Well, searching this thread is a Herculean task. I just tried to find one of my earlier posts so that I could update a link therein. I failed .....
So, the reason I am here: With the time elapsed, the effect of IACV Failures vs. the effect of Engine Mount Failures became much more clear to me. I have updated my earlier note accordingly. If you are interested, read it here: https://drive.google.com/file/d/1Npo...ew?usp=sharing
Thank you for posting this repository of good info; it is important to cover the motor mounts and the IACV all at once. I'm not sure which of them fried my ECU because it wouldn't even connect to any scanner program. I suspect it was the motor mounts, but they are disonnected now anyway, and IACV replaced.
Junkyard replacement ECU can be had for $50 or so and Silca SBB key programmer or Datascan software to reprogram the old key to work and its all good. Better after the leaky fuel pressure regulator, torn intake hose, faulty maf, leaky power steering hose, bad Chinese ignition coils etc.
Did you ever get an answer to this question? I have the same component smoked in my ECU and also have an automatic 2001 Maxima. I suspect it's from the motor mounts so I plan to disconnect them. Do I need to also repair the ECU or is this component only for that purpose so no longer used if motor mounts are disconnected?
did anyone ever get an answer this this circuit chip being burned? We have the same problem and cannot figure out what that chip is related to!
02-09-2015 | 10:21 AM
