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Re: Sons 01 Neon will not start has me baffled [Re: 440abody] #2338711
07/17/17 11:19 PM
07/17/17 11:19 PM
Joined: Jan 2003
Posts: 32,930
Grand Prairie,Texas
stumpy Offline
I Win
stumpy  Offline
I Win

Joined: Jan 2003
Posts: 32,930
Grand Prairie,Texas
It probably resets with a trip to the dealer for a computer flash.

Re: Sons 01 Neon will not start has me baffled [Re: 440abody] #2338734
07/17/17 11:47 PM
07/17/17 11:47 PM
Joined: Jan 2003
Posts: 27,421
Balt. Md
3
383man Offline
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Balt. Md
Originally Posted By 440abody
Originally Posted By 383man
When you say you cant pull any codes did the scanner come on and communicate with the eng PCM ? Even if in the theft mode the scanner should still go into the PCM. Also you said it wont crank and I dont think the 2001 Neon theft could control the starter as I dont think the starter circuit was wired through the PCM on that year Neon. In the security theft mode it should still crank and start but then the eng will die right away. Did the scanner go into the PCM and read no codes or did the scanner not communicate with the PCM ? Ron


The scanner is not conneecting with the PCM. Will not read anthying, just shows no vehicle connected.

No new keys.

I have plugged and unplugged every conncetor I can get my hands on.

Checked any ground I can find, and all are clean and tight.

I do know that it has an immobilizer for the key in the column.
Currently we only have one key as the other is MIA.

So I need some education on the immobilizer and how it plays witj rest of the system. According to what I can tell, it does block tje crank function and the fuel pump. If this is true then how does it reset?



If it wont go into the PCM or communicate with any modules you have a power/communication problem. The first thing you need to do is find out why the scanner wont communicate. You need to check the power and grounds at the OBDII connector and if they are good check the power and grounds of the PCM. Even if the key module wont read the key the scanner should still connect and communicate so if you diagnose and fix that you should fix the car. I dont remember but do any dash warning lights come on when the key is turned on ? If they do look to see if the "check eng light" comes on when the key is turned on. Many times if it has a PCM problem that "check eng light" wont come on with the key first turned on which it should. It will go out in about 5 to 8 seconds but it should come on when the key is first turned on. Also have you tried to communicate with any other modules ? See if you can communicate with the air bag module or trans module if its an auto. I dont remember what year the Neon got the buss circuit but up to a certain the Neon did not have a buss (communication system between modules) and the PCM communicated over the SCI circuit. For the other modules the DRB III scanner turned on an internal buss to talk with the other modules. Thats why I would see if you can communicate with any of the cars modules. It also may have the SKIM system which is the ign node (SKIM module) or key module as many call it and if it does you should be able to talk to that module with a scanner also. Ron

Last edited by 383man; 07/17/17 11:53 PM.
Re: Sons 01 Neon will not start has me baffled [Re: 440abody] #2338748
07/17/17 11:58 PM
07/17/17 11:58 PM
Joined: Jan 2003
Posts: 27,421
Balt. Md
3
383man Offline
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Posts: 27,421
Balt. Md
From what I remember there is no reset on the SKIM system which stands for Sentry Key Immobilizer. You can try unhooking the battery for about 15 minutes as many times that wakes up electronic items. If it is a SKIM problem it would most likely need that module replaced and programed. But you should be able to communicate with the modules on the car with a scanner. Ron

Re: Sons 01 Neon will not start has me baffled [Re: 383man] #2339166
07/18/17 04:07 PM
07/18/17 04:07 PM
Joined: Jan 2003
Posts: 4,395
The Pale Blue Dot
Skeptic Offline
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The Pale Blue Dot
Checking connections isn't enough, at this point you need to access the PCM and check for B+, switched B+ and ground at the PCM.
To do that you will need to be able to connect directly to the harness side terminals-DO NOT PIERCE THE WIRES! Having the proper test leads will also let you check the harness terminals, they can go bad. Then check the wires under a load, most test lights don't provide much of a load. If a circuit fails the test- ie light does not come on, then it's bad, if the light comes on, it MAY be good- there may only be 1 or 2 strands of wire making a connection and not enough to power up the ECM.
I have a headlight that I use to load the circuits and it still let me down on a bus I was working on. In that case the fuse block terminal was going bad and under a prolonged load the terminal would go open circuit. I doubt you have this issue, but there you go.
If you have good power/switched power and ground @ the ECM, well it's time for a new ECM. HTH, Steve

Re: Sons 01 Neon will not start has me baffled [Re: 440abody] #2339244
07/18/17 06:11 PM
07/18/17 06:11 PM
Joined: Jun 2003
Posts: 21,429
It's a dry heat
gtx6970 Offline
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It's a dry heat
Is it a grey key or black?
Grey is SKIM system / Black is not

The only way I know of to ck and see if the PCM / SKIM module is communicating with the key or not is via the Mopar DRB system.
AKA, a trip to the dealer.

The way a SKIM system works is if the module doesn't recognize the key used to start it, it shuts off. Do this I think 3 times and it no loner allows the key to even turn the engine over.

Last edited by gtx6970; 07/18/17 06:21 PM.
Re: Sons 01 Neon will not start has me baffled [Re: 440abody] #2339446
07/19/17 12:44 AM
07/19/17 12:44 AM
Joined: Mar 2003
Posts: 4,848
Memphis
HemiRick Offline
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Memphis
If when you turn the key on it does not flash the check engine light the PCM is dead most likely


Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
Re: Sons 01 Neon will not start has me baffled [Re: 440abody] #2341059
07/21/17 05:47 PM
07/21/17 05:47 PM
Joined: May 2004
Posts: 533
North Dakota
440abody Offline OP
mopar
440abody  Offline OP
mopar

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Posts: 533
North Dakota
So today we checked the PCM and with the plugs disconnected from it we could get the relays to actuate when the key was turned on and in the crank position it would crank (was using a test light to check for power and noticed it tried to crank when he stabbed that pin, and that the relays were clicking as well). Soooo... Correct me if I'm wrong then this is definitely a bad PCM or does it just need to be reprogrammed?


73 Dart Swinger 440/727 8.75 w/3.55's
34 Ford 3w coupe with a soon to be 1958 392HEMI!
Re: Sons 01 Neon will not start has me baffled [Re: 440abody] #2341584
07/22/17 06:40 PM
07/22/17 06:40 PM
Joined: Mar 2003
Posts: 4,848
Memphis
HemiRick Offline
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HemiRick  Offline
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Posts: 4,848
Memphis
Yes sounds like bad PCM be warned I once replaced the PCM in 1 of these cars and it ran for 15 minutes {warm up and trip around the block} before it killed the new PCM......the car went to junkyard after that


Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451
Re: Sons 01 Neon will not start has me baffled [Re: HemiRick] #2341780
07/23/17 01:07 AM
07/23/17 01:07 AM
Joined: Mar 2007
Posts: 858
Southeast Pa.
SALEM1912 Offline
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Posts: 858
Southeast Pa.
Jumping in late on this but the first thing you want to do is get it cranking. In doing so you will most likely find why you can't access codes. If The skim theft system was activated it would still allow you to crank and even start and run for 2-3 seconds. Go back to basics(battery,battery terminals ground wire) and find why it won't crank. If you stab a wire and got it to crank you may have a ground issue some where. Somewhere in this diagram is the reason it won't crank;(PCM supplies the starter relay with a ground so if you think it is the PCM then ground that wire and it should crank in the crank position.

01neon starter.gif
Last edited by SALEM1912; 07/23/17 01:25 AM.
Re: Sons 01 Neon will not start has me baffled [Re: SALEM1912] #2344523
07/27/17 10:08 PM
07/27/17 10:08 PM
Joined: May 2004
Posts: 533
North Dakota
440abody Offline OP
mopar
440abody  Offline OP
mopar

Joined: May 2004
Posts: 533
North Dakota
Things have been busy and i will look into it this weekend andet you know.


73 Dart Swinger 440/727 8.75 w/3.55's
34 Ford 3w coupe with a soon to be 1958 392HEMI!
Re: Sons 01 Neon will not start has me baffled [Re: 440abody] #2348155
08/03/17 10:22 PM
08/03/17 10:22 PM
Joined: Jan 2003
Posts: 8,138
New Mexico
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New Mexico
So what fixed it?

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