Cummins ISX ECM Repair Service

Your own ISX ECM comes back rebuilt, not a replacement

This is a repair service for the Cummins ISX engine control module. You send us the module off your truck, we rebuild and test it, and that same unit ships back to you.

The ISX ECM controls fuel delivery, injection timing, emissions functions and the diagnostic data your scan tool reads. When it fails you usually see a no-start, no communication with a scan tool, or fault codes that keep coming back after the sensors have been changed. Diesel ECM Exchange repairs diesel control modules at board level for owner-operators, fleets and the shops that diagnose them.

Match your ISX ECM by the part number on the module

Select the part number printed on your module. This page covers nine Cummins ISX part numbers: 3103533, 3408501, 3680509, 3681404, 3681405, 3682729, 3683289, 3684009 and 3684275.

If the label is unreadable or you cannot find the number, select the Not Known option. It is the same repair service, and you do not need the number to order.

EPA certification data records the ISX model years each number was certified against:

• 3684275 covers ISX model years 2006 to 2008
• 3683289 covers 2003 to 2006
• 3682729 covers 2002 to 2006
• 3681405 covers 1999 to 2002
• 3684009 covers 2006 only
• 3408501 covers 2002 only
• 3680509 covers 1998 only

Two of the nine need a note. 3681404 does not appear in the EPA ISX tables at all, and 3103533 is certified against Cummins ISM engines rather than ISX. We repair both, and neither is described here as an ISX-certified part.

Listings in this category often identify a module by its Cummins CM generation instead. This page matches on the part number, because that is what is printed on the unit. If the number belongs to a different Cummins engine, the wider Cummins module catalog lists every platform we cover.

Repair your own ISX ECM, or buy a rebuilt one

We fix this failure two ways:

• This page, the repair. Your own module goes on the bench and comes back to you, so your unit is the core and there is no core charge. The trade-off is downtime: the truck is down for the round trip, not just the days on the bench, and the module has to come off before you order
• A rebuilt ISX module bought outright, programmed before it ships, on its own page as the ISX ECM exchange unit. It costs more, and its lifetime warranty starts when your old core goes back. What you get is uptime: your module stays in the truck until the replacement lands

Other paths exist and we sell none of them:

• A dealer ECM carries dealer pricing, with the install a separate cost
• A salvage ECM has had no rebuild and no bench work, so any protection on it travels with the seller
• A core deposit program holds a refundable deposit until your old unit is inspected and accepted. We take no deposit

If your engine is an ISM or an ISX15

Five of the nine part numbers here also appear on our Cummins ISM page: 3103533, 3408501, 3680509, 3681404 and 3681405. EPA certification data records three of those five, 3408501, 3680509 and 3681405, against both the ISM and the ISX engine families. We service all five on both platforms, so order from the page that matches the engine in the truck, not the number alone. For an ISM, use the ISM page.

The ISX15 page is separate and handles 4358814, 4384413, 4993120, 5290170 and 5317106. None of the nine numbers here is one of them, so if your truck runs an ISX15 or an X15, order there instead.

Do I need to take the ECM off the engine before I order?

The module has to come off the truck, because the repair is done on your own unit. Order first, then remove it. The pre-paid shipping label arrives after purchase, so it is waiting when the module comes out.

What does it cost me to ship my module in?

Nothing. After you order, we contact you and send a pre-paid shipping label. You box the module, put the label on it, and send it. You do not arrange the carrier.

How long will my truck be down?

Allow 3 to 5 business days on the bench once your module reaches us, then 1 to 3 business days for delivery back. Transit to us sits on top of that, so plan the whole round trip rather than the bench time.

What happens if my ECM turns out not to be repairable?

It happens rarely. When it does, every dollar you paid is applied to a rebuilt replacement rather than written off, so you end up with a working module either way. A doubtful unit is worth sending in.

Is there a documented reason these modules fail?

Yes, on the CM871 generation. Cummins filed a campaign document with NHTSA covering ISX CM871 modules shipped with a mis-applied RTV sealing bead that let moisture in. A separate Cummins document, received by NHTSA between 2010 and 2014, records engine shutdowns and fault code 1117 caused by cracked solder joints inside ECMs. Both are faults inside the module itself, which is why a board-level repair is a real option.

What actually happens to the board?

Failed components and known high-failure components are replaced and resoldered, and cold solder joints are found and reflowed. We then confirm the module communicates, takes programming, and that programming and parameters store and hold rather than just load. It is voltage tested before it ships. See the warranty terms for the conditions.