I just bought this 14 Maxima S from an auction with a bad engine (rod through the block) Replaced the engine.
Somehow I blew the master fuse (it wasn’t blown when I got it, I was able to turn the car on to roll down the windows) Then I realized I had the shift cable connected incorrectly- transmission was in park but the shifter was in drive. I corrected that. Here’s where I admit to some stupid stuff. I laid a light bead of solder across the master fuse. Blew it. Thought it was too light, laid a thicker bead. Then it started and I let it run for about 25 minutes. I shut it off a couple of times during this time.

And then… idle raised, headlights came on (they were off, not on “auto”), check engine light (intake valve timing and vent control valve), tach stopped working and then the engine wouldn’t shut off. (had to pull the fuel pump fuse). Replaced the fuse, reconnected the battery and it would start but not shut down. After that all it would do when I connect the battery I turn the car to the on position, and then the headlights and running lights come on (headlight switch is off, not on auto), radiator fans come on, and the starter does not engage. The only way to get things to turn off is the disconnect the battery, the start button does not turn things off. I have gone as far as putting a new ground from the battery to the body to the transmission. I’ve checked all the fuses, and all my connections. I purchased a used ECM with no change in results.

It’s a long post but I didn’t want to leave out any possible details.

Any ideas or suggestions? Thanks

The radiator fans coming on means the IPDM can't hear the ECM on CAN. The car not shutting off probably means the IPDM also can't hear the BCM. Check all your fusible links on the battery card and in the fuse and relay box, chances are a subordinate link is blown someplace.

I pulled every fuse, and replaced the battery fuse/card and rechecked the clear fuses there. I will find a way to check the relays.

When the IPDM (that is the “board” that holds the fuses under the hood, right?) goes bad, can damage be seen in its underside?

It's unusual, but every so often I have seen IPDM mainboards that got hot when they failed and left big brown or warped spots in the plastic. Yours has to be alive (since the fans are coming on), but it may have failed in a way that rendered it incommunicado on CAN. That isn't impossible.

I’ve checked all my grounds and checked all my fuses on the IPDM I have power to both sides of every fuse. I checked all my relays also by applying battery power then checking the continuity in the other two pins. I also took apart the IDBM and there is no physical sign of failure on the circuit board. From all the reading I’m doing, it would appear to be either the IPDM or the BCM. Is there any way to confirm without going to the dealer or independent shop? I’m thinking buying a used IPDM would be a good starting point.

Any idea what years and models I can get the IPDM from?

Go into NissanPartsDeal.com and put in the VIN, that will give you the original p/n. Then do a "change vehicle" and close out the VIN, then search the part number in the search bar without any vehicle selected. The bottom of the page will show you what MY's it fits.

VStar thank you for all your assistance. It wasn’t the ECU or IPDM, it appears that it was the BCM. I got a replacement yesterday and even though, as expected, I can’t yet turn the car on it will allow me to turn on the headlights which it would not let me do with the old BCM.

Hopefully just one more question- by coincidence, I’m having a locksmith out to program an additional key fob for my daughter’s Altima. Could the locksmith reprogram the Maxima key fob and have all be good? Or is there more to the BCM than just having it recognize the key fob?

The BCM needs to be configured. Depending whether it's new or used:
NEW: It may or may not take a key program before configuration, and may or may not start the car even if it takes it. Usually they won't take a program before they're configured.
USED: It won't take a program with the existing fobs, you'll need to get new fobs for it. The old fobs will be paperweights. The configuration may or may not be correct, so if you notice anything which doesn't work or works incorrectly, chances are that's why.

Oh crap, I forgot about not being able to reuse these fobs (after 2013?).

So… this used BCM, also from a 2014 Maxima, may or may not operate all systems properly. Understood. Do you happen to know if an aftermarket fob can be reprogrammed? I am having a key service/locksmith come to my house early this week for my daughter’s Altima and if I may have him make a fob for this maxima. Now, here’s the hypothetical- if that fob works but not all the systems work, I would need to have the dealer configure the BCM. Do you know if I lose out on that aftermarket fob and need to have yet another one made after the dealer configures the BCM?

goatmanmitch wrote: ↑

Sun Feb 05, 2023 1:17 pm

Oh crap, I forgot about not being able to reuse these fobs (after 2013?).

So… this used BCM, also from a 2014 Maxima, may or may not operate all systems properly. Understood. Do you happen to know if an aftermarket fob can be reprogrammed? I am having a key service/locksmith come to my house early this week for my daughter’s Altima and if I may have him make a fob for this maxima. Now, here’s the hypothetical- if that fob works but not all the systems work, I would need to have the dealer configure the BCM. Do you know if I lose out on that aftermarket fob and need to have yet another one made after the dealer configures the BCM?

You don't need to pay dealer price for new fobs, the China-cheap fobs on eBay generally work fine. Just get the Nissan part number for the OE fobs and make sure you get an equivalent for that. The aftermarket fobs are no different from OE fobs in terms of function, so reconfiguring the BCM at some later date won't affect them at all.

Awesome. Thank you again for all your input!

I think this car hates me. So, I had my replacement body control module in the car. I had a mobile locksmith come out and see if he could program a new fob. I did not have the pin number for the replacement BCM, so we tried a few of the four digit numbers that were printed on the replacement BCM. First one did not work, then the car stop communicating all together. Now the car is exhibiting all of the same issues as the old BCM. The car suddenly is recognizing the key fob again, and as soon as the ignition is on the headlights and radiator fans turn on. Perhaps I blew the replacement BCM?

The unlock code should have been one of those 4-digit numbers on the label, so it sounds like it took the program but the original problem wasn't the BCM, so it didn't fix anything. Start by getting a full scan and finding out which systems in the car aren't communicating. You're throwing parts at a problem which, at this point, isn't likely to respond to parts throwing.