Where is the PCM

[BigRedWeather]

Can someone help me locate the PCM (Powertrain Control Module)? I also need so help determining:
-if power is getting to it
-if power is getting out of it to components it supplies
-if it is bad

I have posted some pictures. Can you use them to answer these qauestions? Your help would be much appreciated. Enlarge the pictures to fill your screen so you can read the labels I have added.


Attached are three pictures, with filenames:

Inside Cab #X.jpg
Behind the emergency brake and the clutch pedal is the back side of a connector

I have labeled #1. Connector #2 is not visible in this picture.

Inside Cab #Y.jpg
This is a picture of connector #1 (the same connector #1 that is in Inside Cab

#X.jpg.) and connector #2

Under Hood #Z.jpg
This is a picture of three connectors (A, B and C) under the hood that are

coming through the firewall right by the steering column. I ASSUME, but am not certain,

that Connector C is #2 and B is #1. A is not visible in pictures #X or #Y


What is motivating my questions:

11/2 I started my truck on a 30 F degree morning, (we have had a few other mornings

this cold and it started and ran fine). Three minutes later as I gave it a little "gas"

it died. It would still turn over after this but the WTS (Wait To Start) light never

came on. After reading on some forums I verified that fuse #22 in the fuse box under

the hood right above the steering column is good.


97 F350 PowerStroke 7.3L.


Thanks,


BigRedWeather

 

[dpantazis]

bigred-

i am pretty sure that its "C" in pic 3. the 10mm bolt in the middle draws the connector into the pcm.

its behind a cover under the dash in the cab. read the vendor docs on installing chips for details

 

[dpantazis]

bigred-
to answer your specific question- PCM connector is "C" in pic 3. the 10mm bolt in the middle draws the connector into the pcm. the two nuts above and below hold it in.

its behind a cover under the dash in the cab. read the vendor docs on installing chips for details on removing and installing-

http://www.itpdiesel.com/other/DP-Tuner/DP-Tuner_Chip_Install_94-97.pdf

i am also pretty sure if you have idiot lights on the dash the pcm is propably getting power.

more importantly- how good are your batteries? age? voltage?

i think the common sense approach would be to check batteries first. then report if the tach is moving when cranking (CPS sensor working?) then check the glow plug relay. glow plugs and relays do go bad.

DO NUT USE ETHER to start the truck!

then after those simple checks, we can detemine what to check next.

checking if its working is a different issue. the BEST thing to do is use a code reader or OBD program to talk to it to see what codes its throwing.

PCM's do go bad, but rarely.

dennis

 

[HorseHauler]

UPDATE

My Dad is the original poster, so we are working to get this truck working again.

First off, the only bad fuse on the truck was the #6 fuse under the hood, which has been replaced. Nothing has changed. The new fuse remains unblown, however the wait to start light doesn't come on, the rest of the dash lights do work, (I'm told that the wait to start lights only source of power is the PCM) the tach does not move a bit when cranking, and the truck doesn't start.

He bought the truck a few months ago, so we really don't know about the batteries. However, they're showing over 12 volts, and he's even put a trickle charge on it to make sure they're juiced up. Contacts are clean, cables are good.

The altenator went bad about a week ago. He became aware of this when the tach, odometer, and speedometer started going haywire, the idiot volt gauge in the cab got down to 8 volts, and then when he had to jumpstart to get going. New altenator, a week later this happened.

 

[dpantazis]

sorry for the double posts before.

do you have a code reader? beg, borrow, steal one. report the codes back to the list.

i still think that you should eliminate the glow plug system first before jumping to the conclusion that the PCM is bad. yes, the PCM controls the

shamelessly copied and pasted fro dieselman's site-
http://www.intellidog.com/dieselmann/tech.htm#nostart

"After checking the preliminaries, KOEO and Continuous codes, and the concern happens cold only, check the glow plug system function. Unplug the Engine Oil Temperature sensor and turn the key to the run position. This will cause the PCM to close the glow plug relay for the maximum of two minutes. Check for voltage to and from the glow plug relay. The control voltage is supplied by the ignition switch and the PCM controls the ground based on EOT. "

No tach movment- did you replace the CPS? see this page-

http://www.superdutydiesel.com/forums/showthread.php?t=96

"On 2001 and older trucks, you can use the TACH needle to troubleshoot a CPS failure. During a long, extended crank with no start, the TACH needle should bounce ever so slightly. Maybe 100 RPM or so. ... If you get NO NEEDLE MOVEMENT, ... its very likely you have a failed CPS. "

 

[94f450sd]

i would say the CPS died.go the cheapest route first unless you can get a scanner on it to check codes.can get the CPS off Ebay for under 100 bux.buy 2 so you will have a spare.

also where are you guys located?you may have a member that is close enough to be able to come over with a scanner or give you a hand with it.

 

[Crumm]

To answer your first question: C in picture #3 is the PCM. To remove it you unbolt it and pull it out.


It would be best to get a code reader and see what it says but if that is not possible I would start with a CPS. The pcm may end up being the culprit due to "the idiot volt guage in the cab got down to 8 volts, and then when he had to jumpstart to get going". The pcm doesn't like this kind of abuse but they don't fail on a regular basis. I did have to replace mine about 4 years ago but I am still on my original CPS..

 

[action4478]

Did he say if he had a CEL?