97 Expedition stalling, then theft light blinking

[PO'dexpd'nowner]

http://wiki.answers.com/Q/What_is_a_PCM_Relay

http://wiki.answers.com/Q/What_does_a_PCM_power_relay_control

http://wiki.answers.com/Q/Is_a_fuel_pump_relay_and_a_PCM_relay_the_same

http://wiki.answers.com/Q/What_does_pcm_power_relay_mean_on_ford_explorer_1996

"The PMC stands for Power train Control Module. it controls various sensors and relays throughout the engine, by sending voltage singles according to what the sensors receive."


Like I said, smart relay. If it's screwed the whole rig is screwed, but if it get's tons of bogus information from other bad sensors, unexpected intermittent connections and or shorts, it will send the rest of the system in to a frenzy.

The PCM Relay must have solid connections for power and solid communication paths or the rig will act horky. All you can do is check and clean these connections and clean\replace the other sensors, the PCM relay isnt meant to be opened up and have dust blown out if it etc.

ex:

"The PCM control the fuel pump relay on this vehicle. In addition, the fuel pump relay gets powered up from the red wire from the PCM power relay.

Anything preventing the PCM from waking up or anything preventing the PCM power relay from working will prevent the fuel pump relay from activating and of course will keep the fuel pump from getting power."

You've got me a little confused now. Are you saying the pcm and the pcm relay are one and the same? I tried a new used pcm but was thinking I need to check the relay now...since issue never changed. Are you saying I need a new pcm or a little (cheap) relay

 

[Captain Morgan]

I see your point, and I think the nomenclature does confuse.

The PCM is a brain, it makes decisions and controls and switches other relays and systems. It has a relay and fuse all unto itself.

The PCM is expensive because it's a mini computer containing a processor like a smart phone and is designed to be rugged enough for automotive use.

What is a Powertrain Control Module?

You know what a PCM and relay look like by now, and know that they both have mechanical\electric connections. Checking the connections and cleaning applies to both. If there is any, ANY intermittent connections this brain will throw a knee-jerk reaction and start telling your vehicle to do bizarre things to compensate which could lead to a series of reactions.

Check everything, contact by contact. If we don't hear the sounds of scraping and sandpaper your buying the whole forum beers

But seriously, wouldn't you kick yourself if after all this time and money the problems stems from a short in the wire from an 02 sensor? Or a loose relay connection?


.

 

[CARO'S98EB]

if you look at the fuse layout posted earlier there is a PCM relay in the fuse box [battery junction box]. This is not the pcm it is the relay that turns the pcm on. that being said I would also ck in the left front wheel well for and damage to the large harness on the frame rail.

 

[PO'dexpd'nowner]

Can't do anything today b/c my boy has some friends coming over for a campout/grill out. But I plan on replacing all fuses and relays show on the wiring pic that's related to the pcm. Anyone know what that autozone link was then? It wasn't a pcm and it sure as hell didn't look like any relay I've seen.

http://www.autozone.com/autozone/pa...WD/_/N-j90ovZ9cj87?itemIdentifier=953750_0_0_

 

[Captain Morgan]

Unfortunately we can't trust pics on the web. The actual part one would get in the store may not look like what they conveniently posted online, and there may be more than one mfr for a part and thus the housing could be slightly different.

The PCM in the link you posted made by Wells has 16 actual pins. Whatever PCM you find will have the same pinout.

Campout sounds good! I wish I was in the woods this weekend. Yesterday I recalled driving down a stretch, I think it was South of Lexington. The road winds around under a canopy of trees, just beautiful. Maybe it was the Bluegrass Parkway, I can't recall.

 

[PO'dexpd'nowner]

Campout sounds good! I wish I was in the woods this weekend. Yesterday I recalled driving down a stretch, I think it was South of Lexington. The road winds around under a canopy of trees, just beautiful. Maybe it was the Bluegrass Parkway, I can't recall.

Not me...too dang hot!!! I do about 30-45 minutes of work and then back in the A/C for a beer and then back out.

The BG (Bluegrass Parkway to you) is 7 miles from me. I live 47 miles south of Lexington down the BG by Bloomfield exit.

Dunno for sure if it's going to be a campout or not. I don't think they can sleep outside in this heat. We planned on having a bonfire tonight too but may reconsider b/c it's so dry. I mowed down a bunch around the woodpile and will be keep my tractor and water hose very close by if we do. And it won't be in the woods. I live on a small 14 acre farm so it'll be somewhere on it....prolly close to the house in case they get scared, need food/drink or bathroom. Three 8 year old boys.

We got a PILE of meat for the grill ready...pork chops and chicken and 2 bottles of Sweet Baby Rays!!

 

[PO'dexpd'nowner]

Unfortunately we can't trust pics on the web. The actual part one would get in the store may not look like what they conveniently posted online, and there may be more than one mfr for a part and thus the housing could be slightly different.

The PCM in the link you posted made by Wells has 16 actual pins. Whatever PCM you find will have the same pinout.

Just had a thought.....if the Autozone link is a PCM, could I get it flashed to my current code? If need be, could I buy it and have the dealership flash it? Either way it would save me several hundred dollars.

 

[Captain Morgan]

Go ahead . . taunt me a second time! BBQ sounding so so good.

So have you ever been to the "White Barn"?

I'm not sure about flashing that firmware. It should come with the revision that it needs. After all, that's half of what you're paying for.

 

[PO'dexpd'nowner]

Go ahead . . taunt me a second time! BBQ sounding so so good.

So have you ever been to the "White Barn"?

you'll have to clarify "white barn" as I have a 40x60 white metal barn behind my house.

 

[Captain Morgan]

Oh well I guess you go every day then

I had some hottie take me to what could only be described as a "ho down" at a place called the White Barn.

Swing yer partner round and round . . yee haw!