'04 Neon died and won't start, everyone stumped, please help!

While driving my '04 Neon yesterday doing about 60mph, my car suddenly (with no check lights, strange sounds, or overheating) lost all power, RPMs went flat, and my tranny (auto) seemed to downshift on it's own. The car lurched forward and the tranny wound up and came down with the speed, like if you were in a 5-speed in 5th gear and shifted down to second going too fast. So I got it over on the side of the road, and although all the accessories work fine, nothing happens under the hood when you turn the key. No starter, no fuel pump engaging, nothing. The battery is fine, the fuses are fine, the fusible links between the batt, starter, and alt had perfect continuity, unplugging the MAP sensor did nothing, and the relays in the fuse box looked fine. Borrowed an OBD II, but apparently the OBD port in my car doesn't work because the OBD doesn't register a connection. Tried it on my cousin's car and it linked right up. By the way my neon is a front end salvage, which is why I wasn't surprised that the OBD port doesn't work. Anyone have any idea what could be going on? I've explained this to every auto-guy I know and everyone's stumped.:confused:

1) usually the DLC connector and the cigar lighter is on the same fuse.
There's no battery to the ignition switch, or unswitched circuits!
2) Did you have the battery charge and load tested?

danielsatur (http://www.automotiveforums.com/vbulletin/member.php?u=559976)- I checked the battery with my multimeter and it was putting out a steady 12.5v dc. Didn't bother checking amperage because the voltage was good and all the accessories still work. Also tried jumping it but got the same results. Absolutely no sound from under the hood. I looked over the smaller fuses several times, didn't pull them all, but I should have noticed if one was blown. I'll double check the lighter/DLC fuse and post my findings in a few. Thanks for the reply/advice.

Can you turn the bright lights + honk horn ?
Don't forget to check relays, loose connections, and battery cables for corrosion.

Cig lighter works, fuses appear fine, brights and horn work fine. Tried starting it in every gear so I don't think it's the neutral safety switch. Still stumped...

Doe's the electric starter actually turn the engine over, and the engine don't start?

No power to starter. Nothing happens under the hood when I turn the key. No clicking, whining, beeping, humming, nothing. The accessories work though and what would explain why it died while I was driving?

Ok, day two and still not fixed. Today I'm going to check the ignition circuit, CMP sensor, and CKP sensor. From what I've read and been told, these are about the only things left that could come close to explaining what's going on, besides some strange electrical/wiring problem. Thanks for the replies and keep the suggestions coming. I'll let ya'll know if I get it fixed or put it in the shop.

You need battery for the starter, fuel pump, and ECU.
What's common?
Ignition switch, and security system.
Doe's this car have a Auto shut down relay?
It's used to disable/trigger both the ignition system and fuel system.

Hopefully these will get you started. Start with the red power feed wire to PDC and work from there.

I would focus on the starter motor relay 1st!
1) Roll the relay with one, that has the same #'s

Thanks for the pics job53.

Got it! When I checked the fuses last night, I used a bulb tester, and only paid special attention to the fuses dealing with the ignition system. On a hunch, I decided to double check the ASR and fuse again. ASR had continuity where it should and didn't where it wasn't supposed to. Checked the fuse with my multimeter this time and got mixed voltages from the top posts. Pulled it and low-and-behold, when it blew, the molten filament fell towards the opposite post and made a short. There was just enough current to light up the test bulb, but not enough to work. Switched it out and it started right up! Only thing is, now my power steering pump is squawking. I went to pull it up from the yard to my parking spot by the garage, and there was no power steering. Checked the fluid and it was low, so I topped it off and now I have PS, but with a lot of noise. But I can deal with having the PS pump changed. Now I just gotta figure out what caused the fuse to blow. I found a post from a guy who was having the same problem, but his must have had a different cause because he fixed it by grounding the 87 post of his ASR. I mention that because he said once he could start it, the OBD II would link with his car. So I guess I'm off to AutoZone to get it again and see if it'll tell me whats going on. Thanks again for the replies!

See what kind of power steering fluid is used, because it could be AFT.
Flush the power steering system by using a turkey baster for removal, and add fluid.
You might consider using lucas power steering additive.

Topped off the power steering fluid and it works fine again. Must be a slow leak somewhere, but I'll figure that out when I do my tune up. Scanned my car with an OBD II to see if I could figure out why the ASR fuse went, but it came back with no codes. I guess for now I'll count it as moisture or some other random fluke. Thanks for the replies. If something else related to this goes wrong, I'll post it here in case some other unlucky person has to go through this.

A shorted H02 sensor wire can burn a ASR fuse!
Do a visual inspection on your H02 sensor wires.

I'll definitely take a look at the HO2 sensor then. I did a tune up on it today and found the #2 spark plug was loose. I'm wondering if it got jostled when it died on me and the comp detected it and threw that fuse? Ran the OBD II again today just to be sure and it's still not pulling any codes. I'll check out that sensor though and let you know. Thanks again for the replies =]

I found it. According to the diagrams in my Haynes manual, the only things directly wired to the ASD besides the fuse are the PCM and the Alternator. The ASD interacts with everything else via the PCM. So I started at the Alternator and traced the wires up to the PCM and I found where the short was. The loom with the alternator wire in it had been pinched against the front of the tranny when the previous owner wrecked it. The shop that fixed it must have missed it. So I opened the loom, then spliced, soldered, and taped the damaged wires, and now it's all good =] Thanks anyway.