STUMPED.

[Turbo30]

Hey guys, it's been quite some time since I've last posted. I can not figure out what is going on here.

I have an 03 Bonneville SE with 200,500 miles on it.

The engine randomly shuts down without a spit or sputter and throws no codes.
Even worse.. the car shuts any and all scanners down that have been hooked up to it... ??????????
I changed the fuel pump and the MAF sensor this morning since i figured with it shutting down randomly.

my fuel pump was running 42-48 psi this morning very erratically. the new fuel pump was at 45 securely.
i disconnected the MAF sensor and it made no difference in the performance of the car and threw no codes..

the car ran great after the new pump and sensor for the 24 miles to work. then the car shut off on me 3 times at 60+ MPH on the way home with absolutely no warning or sputtering... I'm at a total loss here.. any ideas?

[SSEiMan01]

The car not linking to scanners sends up a flag in my head that says you have a bad PCM.

Though it could also be a lot of other things if its not that, I would guess Crank Sensor and / or ICM.

[Turbo30]

i haven't changed the fuel filter yet......... you think that might be part of it?

[nos4blood70]

I would try that crank sensor first.

[SSEiMan01]

Could be if it has all 200k on that filter. But that wouldn't prevent the PCM from reading.

Might be worth asking Haro for a PCM. At least that way if its not that you're not out hundreds. Just my .02

[00Beast]

I doubt haro would have an SE PCM though.

[SSEiMan01]

Its always worth asking.

[CMNTMXR57]

Lack of ability to scan with a scan tool tells me loss of class 2 communications through it's network which means the PCM isn't communicating with anything (why? Could be a bunch of reasons), and as such, won't run without said communication.

Now why's? Shot PCM, major short in the harness, bad connections in the harness connector to the PCM, etc, etc.

[redzmonte]

Definatly put a new fuel filter in it along with other things. Allways do a filter with a new pump. not saying that is your problem but definatly change it.

[StreetƐgl-o21]

Honestly about two months ago i had the Same Issues except for the lack of communication/codes In fact i kept disconnecting my MAF sensor to see if it was the problem but i flooded the PCM with that code so i couldn't find out what else was wrong with it. Turned out to be my Crank Sensor i had to replace like SSEiMan01 stated above.
But obviously i wouldn't just jump into replacing things without figuring out why your not getting any codes.

[vogie01]

Had the exact same issue for months. I replaced ICM, coils, and I even unplugged the MAF with no change. I found a working MAF and tried it out before I start work on replacing the CPS(What I experienced and what you are saying it clearly had to be the CPS). Boom!! Runs great again!! Try to find a friend or family member with a 3800 that has a working MAF. If there is no change when you unplug the MAF, I would start there before rushing to the CPS.

If you do the CPS might as well replace the harmonic balancer as well.

[SSEiMan01]

If the PCM isn't reading that's a problem, not an overlookable coincidence. I would start with the PCM and if that isn't it, which I have a hunch it is, then go to the CPS.

[00Beast]

Figure out why you're not getting communications first, then go to other issues from there.

[StreetƐgl-o21]

Consensus definitely find out why the PCM isn't responding first don't change anything until then.

[2000Silverbullet]

Check the underhood fuse box ignition fuse for good contacts.
I had a similar problem and it turned out to be a bent terminal that made intermittent contact with the fuse.