[k3vin15753]

So this morning i went to the car and pressed the unlock and didn't hear the click sounds of the doors unlocking so i manually opened it with the key and tried to start the car. There is no response at all, no sound cranking no power nothing. So i got my other car and gave the Versa a jump, still it didnt work but the power is back on though and there is cranking this time. So i thought it was the car battery cause it was reading 11.7 on voltage so i changed the battery and tried again. With the new battery installed the lights, radio, etc they all turn on but once i turn it to start the car it just keeps on cranking. So anyone have this problem or know what might be the problem here.

Also when my car was working i would have problems sometimes starting the car on the first turn and usually it would take a second turn for the car to start.

 

[k3vin15753]

I had it towed this morning so my mechanic is checking it right now. I thought it was the key too so i tried the factory keys the car came with and still nothing. I tried all three of the keys i have for the car and still nothing. Also i think i failed to mention this before but my check engine light is on. But the code i got from it was the oxygen sensor so i dont know if that would have anything to do with it cause it been on for over a month so i dont think that was the problem.

 

[k3vin15753]

You've been driving for a month with your Check Engine light on and haven't had it checked?:surprise

Yea lol iv been busy with work so i didnt have time to bring it to the shop till now. I checked the code to make sure it wasnt anything too serious lol only thing that popped up was the oxygen sensor so i figured i could wait a bit :|

 

[k3vin15753]

Does it try to fire at all? Were you using one of the original keys that came with the car? It's most likely a NATS (Nissan Security) problem, i know once in a while for no reason at all (that i have cared looking into because it happens so infrequently) i will get a no start too. Usually if i get that i take the key out for at least a few seconds then try again and it works.

From my educated guess, i would imagine the NATS is just a series of modules that are tacked on to the regular body wiring/control modules meaning that if this is a common problem, the component failures are probably across the entire line. I've actually replaced a few BCM's because of either this NATS problem, but usually more often than not they have a car that seems like it's possessed as well (random unlocking/locking, power steering motor stop working, warning lights erratically on/off). It may be the receiver unit/antenna that sees the key fob or key chip signal and enables or disables ignition accordingly. Not sure if the older Nissan keys have chips in them.

My Mechanic ask me to bring in all my keys cause he checked everything so i think he reached the same conclusion as you, about the NATS. Is it possible that the NATS completely forgets the transponder chip codes from the keys due to the battery completely dying cause i couldn't even unlock the car before? But then again the keyless entry remote works though once i replaced the battery so idk. And anyone know what controls the over head Dome lights cause they have been acting weird they dont shut off when the doors are closed now......so i leave them completely off. is it the BCM?

 

[k3vin15753]

IPDM controls the timer for the lights shutting off. I think part of the problem is that the IPDM is in a particularly bad place where water can leak past. It's in the engine bay on the left side in front of the strut tower, right above the fender liner. Corrosion is probably a big reason why these fail and start causing haywire. The IPDM integrates one big CPU controller, and the function of individual relays in a traditional relay panel. Unfortunately it seems to be less reliable than traditional relays. At least with individual relays you can replace the problem ones, whereas the IPDM is non-serviceable. So if one circuit controller is problematic you must replace it as a unit to fix one problem.

There are certain things in a computer on cars that is stored on what i would call "hard memory", or memory that doesn't require power to sustain. Same as when you put your computer to sleep vs hibernation, sleep puts all the data required for your current state onto RAM which requires power to sustain, whereas hibernation puts it onto a hard disk or solid state drive which doesn't require any power at all to sustain. Much like the odometer data will never leave that vehicle if it loses power, the key stuff is the same. I think it's a NATS module or maybe the receiver acting erraticly that's causing intermittent locking/unlocking issues. Perhaps due to corrosion or bad connections internally, or the CPU/PCB itself.

Jim, i know it's not recommended practice to just drive around with a CEL, but if the customer knows what it is and that it is not affecting anything then it isn't a problem. An H02 sensor code CAN cause poor fuel economy, CAN... it depends on what specific code he has for it. Is it just an O2 sensor heater circuit? Is it the A/F wideband that is a direct feedback to the ECM? Or is it just the post-cat narrowband sensor that simply monitors post-cat gasses and triggers a code based on cat efficiency? Even then, a cat-efficiency (or rather de-fficiency) code is not necessarily grounds for cat replacement, often it is an incorrect A/F caused by something upstream (vacuum leak, incorrect fuel pressure at the rail, clogged injectors or sticking injector pintles). In the case of incorrect A/F, STFT (short term fuel trim) value is a very good way of determining if there's a problem in the fuel delivery or management system.

UPDATE

Well i left the car with the dealer on Friday and got a call from them a little later they told me that there was no signal going to the BCM and that it would cost around 850 to replace it and install new one. They told me they couldn't check what else could be wrong unless i replaced the BCM and that even if after they replaced the BCM and the car still doesnt start it would cost extra for whatever comes next lol. So right now im just hoping once its replaced that will be the end of it.