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Discussion Starter · #1 ·
I tried posting this in the right forum, but I think its just dead. This forum has a lot more people visiting it, and I know some of you guys would know this due to being nissan lovers. Many of you probably had this car at some point.

I have looked just about everywhere, and maybe I'm blind, but I can't find an under hood fuse box diagram for my 2003 Altima. 2.5L automatic. I need the fuse box diagram for that car. And google does pop up with the one in the interior, but I guess the one for under the hood is just lost in a sea of other diagrams that are not for this car. Can someone please help me out? The diagram that was underneath the lid of the fuse box, is useless. All the text and lines have blurred together over the years and its unreadable.
 

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I tried posting this in the right forum, but I think its just dead. This forum has a lot more people visiting it, and I know some of you guys would know this due to being nissan lovers. Many of you probably had this car at some point.

I have looked just about everywhere, and maybe I'm blind, but I can't find an under hood fuse box diagram for my 2003 Altima. 2.5L automatic. I need the fuse box diagram for that car. And google does pop up with the one in the interior, but I guess the one for under the hood is just lost in a sea of other diagrams that are not for this car. Can someone please help me out? The diagram that was underneath the lid of the fuse box, is useless. All the text and lines have blurred together over the years and its unreadable.
I went through the same thing last year. I looked at diagrams until my eyeball were about to fall out, but none as I found had any labeling of the fuses.

There are plenty of diagrams that show the relays, and what each do, but not the fuses [well, they show the fuses in the pictures, but don't tell what each fuse does]. The fuse box you're referring to is called the IPDM.
 

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09 Altima 3.5SE 6MT Sedan
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M is right. Even the FSM only labels the relays. Google is always useful though...

 

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Discussion Starter · #5 ·
Found someone selling one on ebay, and it doesn't seem to exactly match the one that dougmac posted. Looks like I've got one less fusible link. My car seems to be like this pic:

 

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09 Altima 3.5SE 6MT Sedan
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yep, one I found was for the 3.5 (which I have had and recognized). I didn't think the IPDMs would be so different....
 

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Discussion Starter · #7 ·
Well I have identified the fuse that keeps popping. Its the ENG MGT fuse. I believe that means Engine management.

Now I am something of a newbie to this type of thing, so this might sound like a dumb question. But could that be the cause of the no start condition, that I'm dealing with? Is "engine management" directly linked to the starter and the key switch? Or should I be looking elsewhere?
 

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09 Altima 3.5SE 6MT Sedan
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Thanks again Mr D.

That will most likely come in handy in the future.

I wonder how you would fix that issue?
 

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09 Altima 3.5SE 6MT Sedan
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My spidey sense is tingling...and I'm wondering if this isn't another case of those active engine mounts killing the ECU?

My first test would be to disconnect the ECU from the car, replace the fuse and see if it still pops. Pretty cheap as far as isolating the problem goes.
 

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Discussion Starter · #11 ·
Started working on the car again recently. Had to wait a while.

Anyway, I've never heard of active engine mounts. How do they kill the ECU? I'll perform the test and report back. But wouldn't yanking the ECU prevent the fuse from ever even being able to receive power?

I guess I'm just confused as to how that would prove anything.
 

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09 Altima 3.5SE 6MT Sedan
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Google it. As for removing the ECU...the problem is that one part of the ECU circuitry shorts out another....so if your remove the unit, it cannot cross connect those current paths, and no fuses should blow.
 

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Discussion Starter · #13 ·
Yes but with no power to anything, it couldn't blow. Are you saying that there are certain instances, where it could still blow, with the ECU removed?

I ask because I'm a bit of a noob to fixing electrical problems, and I'm still not sure if power would even still be supplied to the fuse (at all) with the ECU removed. The test you're suggesting, would indicate that another problem could still blow the fuse, with the ECU removed. But since I'm going to have to turn the key to perform the test and try to blow the fuse, I'm assuming that power would have to come from the ECU first, before it could ever blow the fuse.
 

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09 Altima 3.5SE 6MT Sedan
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The ECU is just the engine computer...your headlights, radio, power seats, etc etc will all still work even if it is not present. Have a look at the FSM for your year/model (see my .sig below for top level Altima FSM link). Start with the PG.pdf section and familiarize yourself with how the power 'tree' works.

The idea in debugging any short is to first find the 'branch' where the problem is, then either disconnect one twig at a time, or remove all twigs first and re-attach one at a time. My crap analogy should translate into branch=fuse and twig=end device (like horn for instance). Sometimes that is not always easy to do, such as with the ECU and the hundred or so pins that connect to it at once.
 

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Discussion Starter · #15 ·
Well thanks for all the help all. It was of course, something totally dumb. The shifter was disconnected, and the trans was stuck in 1st. So once I hooked it back up and put it in park, the car will start. Didn't know that, as the guy who was helping me to begin with took it off when we were working on it.

But now I'm on my own, and of course, I have a couple more questions.

What would cause the engine to smoke out the tailpipe? Its not horrible, but its still fairly bad. Enough to make you want to leave the area. The engine was recently rebuilt, so that makes me doubt it is the rings. What are some other causes of smoking tailpipe?
 
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