Welcome.

As I’ve an ‘04.0 I’ll be keeping an eye on your thread.

When I can’t find something I’ve found that re-arranging search terms helps (computer, vs ECM, for example).

Here’s an online search example:

https://acsdiesel.com/dodge-cummins-ecu-ecm/

My next search would be to correlate “DODGE CUMMINS 2003” to ECU and then to ECM repair, replace, remanufactured, rebuild, swap, new . . . .

Then

I don’t know the first thing about that vendor, so mixing it in would be part 3. Don’t fall for temptation of zeroing on any vendor, first. Just save. Let that part be last.

1). Keep looking for new search terms.

2). Keep an eye out for savvy contributors.

3). Get part number list.

It’s not unusual these two will combine. Here, online, or at other forums. A quality vendor or vendors will start to show up repeatedly cross-referencing best (1) search term, (2) contributor(s), and (3) part number.

Here’s an example of an in-forum search result where #1 & 2 are met and now zeroing in on #3.

https://www.cumminsforum.com/threads/ecm-compatibility.2572064/

Still a ways to go till one or more vendors.

Etc.

Good luck!

.

 

what is manufacturing date of your truck, info on equipment / modifications

early 03 had ECM on engine , and pcm on fire wall
later 03 had just ECM on engine .

Why did orignal ECM go bad ? Not very common unless bad power and or wiring issue , which should be fixed before installing new part(s)

 

I'm waiting to hear back from the repair shop on the manufacturing date (they have the truck).

I'm fairly certain it is an early 03 with the ECM on the engine and the PCM separate on the firewall.

I'm not entirely certain how the ECM went bad. It seems to have started when we had a battery/charging problem which resulted in the alternator smoking and both batteries being cooked. The repair shop did not identify a definite root cause, but replaced the alternator and the batteries and the problem went away and did not repeat itself for 4 months, then the same thing happened. And this time, with a new alternator and new batteries, the voltage was only ~ 9.5V. To try and keep this short, it was determined the alternator was not being excited and the charging circuit in the ECM was not functioning properly. An OEM pin test was conducted I believe. Some ground issues and a potential alternator cable issue were also identified and fixed. In an effort to not replace the ECM due to cost, a self exciting alternator was installed by the repair shop and this worked for about 150 miles of driving. Then, the truck started to drop voltage down to 7 volts. And, unlike the prior issues, the trans was now not shifting correctly in 1-2 gears and the entire dash went out. The batteries and alternator were fine though this time. At this point, it was determined that the entire charging circuit in the ECM was bad. A loaner ECM from another 03 2500 was swapped in and the issues appeared to have went away. The repair shop has been trying to obtain a reliable ECM since then that will accept programming etc. Two used ECMs have been purchased and neither has worked. One seemed not to be compatible from a pin placement perspective.

The truck is a 2003 Dodge Ram 2500 SLT. In terms of engine/powertrain status: new transmission, turbo has been upgraded, performance intake system and performance cam have been installed. New batteries, new alternator, new cpi. I believe wiring is mostly original.

 

This Repair Shop is a Forum Vendor, send them a PM.

https://www.cumminsforum.com/members/autocomputerspecialist-gm.1029279/#user-business

 

Shop should be using onboard diagnostics to help narrow down issue find out why the issue happened.
Most common issues with these trucks are wiring related.
Big voltage drop like that should show with voltage drop testing.
Dont want to say impossible but there is gonna be side effects to altering the stock EVR (electrical voltage regulation) control components .

Can go to Cummins with VIN and get info for powertrain
Genuine Cummins Parts

Can get equipment list/build info for truck with your VIN .
Equipment Listing (site.com)



Good diagnostics for 03-04 here in FSMs

2004 Dodge Ram - Google Drive

drive.google.com

Other good info here

Newbies guide to your new to you truck

First off welcome to CumminsForum! Lots of smart guys here that have seen a lot. VIN Lookup... https://www.cumminsforum.com/threads/newbies-guide-to-your-new-to-you-truck.1909713/page-11#post-29385439 Service Manuals (PM me if the link is not working, use Adobe to open them) Updated Links...

www.cumminsforum.com

As far as ECM like 9297oldram suggested can contact ACS and discuss , typically they sell plug and play or repair yours and if needed they also repair/rebuild wirng harnesses .


That appears to be late 03 version 305HP /555 ft/lbs federal version with 48re, which AFAIK were all ECM/TCM on engine only version, but if your order ECM from ACS should verify with them .

 

Thank you. I will pass this along to my repair shop. Much appreciated.

 

as a former service writer who STRUGGLED with this on an 05, my honest and best suggestion is try the dealership. YES you're going to pay out the nose for it. YES it may take a bit more time. BUT at least you'll know its a good part and not some junk like flagship one. Now I'm not sure if they'll have an 03 ECM anywhere but its at least worth a shot, worse case you have the repair shop take the truck to the local dealer and have them do all the work. That's what I ended up having to do. But I also worked a deal with that customer that we would split the costs of the ECM because at this point it had been like 4 months on waiting for various ECMs to ship or not ship. Heck even tried a highly recommended company out of Florida and they were hot garbage as well.

 

Thank you. That (the dealership) will likely be the next step. I appreciate the advice. We're at ~ 2 months (some of this was diagnostics) and two garbage ECMs to date. And, we're leery to pull the trigger on another ECM since the company that sold the last one that was defective will not honor the return. Other replies have suggested to use the forum vendor ACS and we are going to reach out to them today. If that doesn't work, then maybe the dealership...

 

I think the dealership would be the last place I would recommend for electrical and ECM issues for these old trucks.

I would be interrogating any dealership very closely before taking your truck there:

• Can that dealership flash and configure a 22 year 2003 ECM?
• Does the actual dealership technician have skill and experience with 2003 Cummins trucks and ECM's?
• Is the actual dealership technician familiar with confusing 2003 Cummins trucks and ECM's?

If the dealership technician doesn't meet this criteria then I would keep researching.
I think you have to get yourself educated on your 2003 truck's electrical and ECM.
A ton of research on this forum.


Read Slowmover's post over again and especially the 2003 manual trans ECM thread that has excellent info on 2003 Cummins ECM's.
Reach out to ACS. Don't trust them until they are giving you good answer's.
Anyone who says all 2003 ECM's and trucks are all alike doesn't have the skill and experience.

I hope you get it figured out..

 

Two years ago my local Chrysler Dodge Ram Dealership COULD not even source a ECM for a 2005 Ram. ACS came through after 2 Tries and my local shop getting a better Diesel Mechanic who found and fixed bad wiring.