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Can I Bench Test My PCM? 2003 T&C

29K views 22 replies 7 participants last post by  sselander 
#1 ·
I have been chasing a no crank condition. I am not getting the ground from the PCM to the coil (# 85) on the starter relay. I also was not getting ground to the coil on the automatic shut down relay (# 85) on that relay either. I discovered a blown fuse, #17 20 amp for the ASD relay. As soon as I put a new one in it blew. I suspected a short in the PCM. I removed the PCM and looked inside but could not really see through the gel if there was an obvious issue. For laughs I re-installed the PCM to check some other parts of the starting curcuit and this time it did not blow the #17 fuse for the ASD relay. I still have the same no crank issue as well as no ground(s) to the coils in the relays.
By the way I can ground the #85 pin on the starter relay and get the starter to crank but not start.

History was the van would not start or crank. I conducted all the tests as outlined in the Haynes manual. I checked all the basics, connectors, under the Integrated Power module for corrosion, wires, the transmission range sensor etc. When I was done checking all of these things it did start. I thought it was a poor connection perhaps. However after a few starts with out driving, it was right back to no crank. I did get it to start again simply by checking it later in the day and it started right up but this time it stalled while running after about 10 seconds bringing me back to the no crank condition I am in now. Then the issue I described above.

Note: I do not have any codes when I check with my scanner. I was thinking a crank sensor perhaps even though it would still crank with a bad one no?

Before I buy a new PCM I would like to test mine. Can this be done? If so by whom? I am wondering if I have some other short passing through the PCM. I am not sure what to check next.

Any other thoughts please let me know.
 
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#2 ·
I would check for continuity to ground through the wires that are blowing fuses. Other than that, I would guess only a very specialized computer could test the PCM.
 
#3 ·
No you can't. One alternative may be to call one of these ecu repair/replace sites and see if they will test it for you. Then again, can you trust them to say "Oh yes, it tests just fine will send it back" instead of making money selling you a rebuilt module? Andygs suggestion is your best route. Verify the continuity/power/grounds are there then bite the bullet. You can get rebuilt PCMs for as little as $250. Even cheaper from a junkyard. Some have had good success with Ebay. Come to think of it I just saw someone buy one from Autozone for $250 with a three year warranty. He was happy.
 
#4 ·
before you send your PCM away (or replace it) take the battery out and take the battery tray out and closely examine the wiring bundle under the tray, it is fairly common on early 4th gen to have H2SO4 (battery acid) leak down and eat away at the wiring harness down there...
 
#6 ·
Atoman, I did remove the battery tray and inspect under the IPM and the wires on the first pass of troubleshooting. However today I will remove it again and look very closely to be sure I don't have an issue as described. It is an odd design with the overflow tube from the battery tray ponting right down at the wire bundles. I will extend that for sure. I intend on going over everything one more time prior to changing the PCM. I will update later today!
Thank guys.
 
#7 ·
Well I went over everything again. The wire bundle looks good. All the connectors, under the IPM, etc. I checked the starter and ignition circuits as well. Still nothing. No ground signal to the automatic shutdown or starter relay coming from the PCM. I checked some items related to the ASD such as the coil pack, injectors etc. No issues. This time the fuse has not blown for the ASD relay-very odd. I can only think I shorted it by accident the first time but I'm not convinced of that. Anyway I am going to send my PCM to a shop in Fla.-Auto Computer Exchange (from Ebay) to be tested and either returned or rebuilt. They state for $124.95. I could do an exchange with a lifetime warranty for $169.00. We will see.
 
#8 ·
Gerty...I can see where you did all the external checks. Great. The silly part...is the Fuse that supplies (+) 12V to the PCM being open.

I'm sure you checked the RPS (Transmission Range Position Sensor Switch) that would give you a Ground (-) from the respective terminals??? with the input to the Transmission Module.??

One thing by sending out the unit (PCM) for checkout / rebuild...is the fact that you can eliminate a large part of the system in Question.

Lots of luck, and hope for a note from the checkout that it did have a problem. That would be super great news! LOL :)
 
#10 ·
Well I sent the PCM to ACE in Florida this past Tuesday. Thursday afternoon the tech called me to go over my issue prior to doing anything to the unit. After I explained all of the tests I had conducted and the fact that I was not getting a ground signal from the PCM, he felt that indeed the issue would lie in the PCM. He was going to let his engineers have at it. I got notification that on Friday afternoon that it was already shipped and on its way back to me! I should have it by Tuesday. I hope there is a report included with the unit as to what was found, if not, I will call and ask if I could have one. I will keep everyone posted..... By the way, including the return postage, it was $150.00 for the repair.
 
#11 ·
PCM diagnostics

I need to send mine out for diagnostics.

After 3 years, my "P0303 Code - Cylinder #3 Misfire" has returned.
3 years ago the O2 sensors, plugs, wires were replaced.
This year, the EGR & ignition module.
Dealer replaced the wiring to number 3 injector a week ago.

I did some research and found one of the oldest companies that diagnoses/repairs them. (1997)
Automotive Computer Supply - autocomputersupply.com
I am going to call them and get a quote.

They explain the short comings of the Chrysler PCM here:
http://autocomputersupply.com/index.asp?PageAction=Custom&ID=6

There is a chart which shows the latest version for the PCM using the Chrysler DART software
http://www.aa1car.com/library/2004/chrysler_pcm_flash_availability.pdf


Automotive Computer Supply now supplies factory replacement PCM's for the Chrysler

I understand also there are PCM's made by the aftermarket companies. (Chinese made PCM's)
 
#12 ·
rebuilt engine computers/ECU/PCM

I have a list of 17 companies that I researched - The BBB reports are revealing.
PM me if you woud like a copy.

These companies below, (based on BBB ratings) deserve mentiion.
To be fair, there are some older, reliable companies not on this short list. (They get great reviews if you google them)
Also, some are being re-evaluated and do not have a rating.
Also notable is a popular company that has an F rating with the BBB.

4/26/11 - BBB auto computer list (B or better)
=======
Auto Computer Supply
http://autocomputersupply.com
======================
Auto ECM Electronics
http://www.ecmdepot.com
======================
Automotive Electronic Solutions
http://www.aesmodules.com
======================
GoECM.Com
http://www.goecm.com/
======================
S.I.A. Electronics, Inc.
http://www.siaelec.com/
====================
Solo Automotive Electronics Inc
http://www.solopcms.com
 
#13 ·
Well I received my repaired PCM back from ACE. After installing the unit the van started right up. However, I now had the ol' P1491 code, radiator fan relay circuit. After some quick troubleshooting it was clear the PCM was not sending the groud signal to the solid state fan relay. I called ACE as they offered a lifetime warranty and they instructed me to ship it right back. I did and await the return of the unit. I did some research and discoverd there is a TSB relatd to a software issue with these PCM's and the function of the fan relay. It requires a simple reflash of the unit. I passed that info along to ACE as I did not have the P1491 issue or any codes for that matter prior to the rebuild. The folks at ACE so far have been very helpful and apologetic at this latest inconvenience. The only negative I would note is they do not supply a report from the tech of what was discovered damaged and repaired. I did ask for it and they were going to see if they can locate the service notes and get them to me. After looking at some of the info sselander posted I am hopeful I get the service I expect.
 
#17 ·
Hmm, no. This was simply purchased from e-bay, they specified that the part # must be an exact match and it was. As was the last 4 digits that are repeated in a box below the part#. Someone mentioned they had luck on E-Bay so i gave it a try. So far im still where i started with a no crank condition. Does plug and go still apply to me? I will email the seller in the AM. thanks again
 
#18 ·
When you buy a properly rebuilt computer, it should be programmed with the mileage and VIN number.
Also, the Chrysler software should be updated to the latest version.

"You can’t simply swap a PCM from one vehicle into another and expect it to work perfectly. If the VIN in the PCM doesn’t match the VIN number on the vehicle, it can complicate scan tool diagnostics, future software updates and vehicle documentation and tracking. That’s why replacement PCMs need to be flash programmed with the correct and up-to-date information."

"There are three methods to remanufacture the ECU. The first one is replacing visually damaged boards. The second is replacing damaged integrated circuits determined by electronic testing. The third option provides programming upgrades to the ECU on top of integrated circuit replacement. Final reliability of remanufactured ECUs depends on the method used."

Please read the Chrysler section on Auto Computer Exchange:
http://autocomputersupply.com/index.asp?PageAction=Custom&ID=5

I carefully researched companies before I sent mine out.

references:

http://www.autocarepronews.com/Article/40520/tech_feature_reflashing_control_modules.aspx

http://autocomputersupply.com/index.asp?PageAction=Custom&ID=5
 
#19 ·
ok, what if i return the ebay module and get a new one from say AUTOZONE, will they do this or do i get a locksmith to do it? If not them then who other than the dreded DEALER? Better yet, what is the best way out of this mess without spending a fortune? send my old unit out like some others have posted? :confused:
 
#20 ·
I would try to return it if you can.
Autozone sells Cardone, which the factory has to program with your info & then sends to Autozone.
Much cheaper to have a reputable company look at it and rebuild if necessary.
Stay away from eBay for them.
Mine is being rebuilt right now.
 
#21 ·
These are the steps the company I went with does:

Rebuilding steps:
•Investigating the trouble codes and symptoms associated with your module.
•External inspection of the module
•Internal inspection and repair, as directed by damage found or manufacturer technical service bulletins
•Functionally testing
•Update the programming on the module
•Functionality retest
•Return it to you

If it cannot be rebuilt, you get a remanufactured module:
•We purchase a replacement module for you and have delivered to our lab
•Internal inspection and update, as directed by manufacturer technical service bulletins
•Functionality testing
•Update the programming on the module
•Functionality retesting
•Ship it out to you
 
#22 ·
Well as I noted I sent my PCM back to ACE in Florida on 4/28 Thursday afternoon after having it rebuilt the week prior. To my great surprise, I already got it back today, Wednesday the 4th here in New Jersey. The unit is installed, working fine with no codes. I still never got the service notes however prior to sending it back I discussed with them the probable need for just a reflash of the software. They stated this is something that does happen from time to time and they would promptly take care of it, and they did.

The only complaint I have if any, was ACE forgot to send a prepaid return shipping label the first time they sent my unit to me as per the warranty. I ended up mailing it back to them at my cost as waiting for an $11 shipping label was not worth my time. I did get one this time just in case! I can say this entire transaction for me was a success albeit it took two trips to Florida for completion. My PCM rebuilt for $150 plus the $11.00 return postage. Not too bad I suppose.

Now time to install yet another set of sway bar bushings and away we go!

Thanks to all for your input and advice.
 
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