The 3126B and 3126E (7AS, 8YL, 9SZ, CKM, HEP) run the 70-pin ADEM III module, so they are in our fastest lane: 3 to 5 days on the bench, programmed back to your engine serial, lifetime warranty. The early 3126 1WM is a 40-pin module and runs 15 to 30 days.
Failed flash recovery available.
On every Cat 70-pin ECM we repair, we upgrade the injector drivers for durability and replace the internal battery.
Sale through October 31: $525 on every Cat 70-pin repair (regularly $745). 40-pin and 120-pin repairs stay $745.
The 3126 is in medium-duty trucks, buses and motorhomes, and its ECM fails the same few ways.
What you see: the battery went dead on the truck or machine, or it got jump started, and now it cranks and won't fire, or it won't do anything at all. It ran fine before the battery died. This is the classic ECM failure.
The quick check: turn the key on and watch the dash. The check engine light should come on for a few seconds. If it never lights up, there's a good chance your ECM is not waking up.
What we do: check the ECM fuses and battery cables first. If those are good, send the ECM in. We get it powering up again, test it on the bench, and send it back programmed to your engine.
What you see: A miss or dead hole that stays after an injector swap.
What's happening: Injector driver failure inside the module.
What we do: We rebuild the driver circuit and bench-fire every channel.
What you see: No tool will connect to the ECM.
What's happening: Data-link circuit failure.
What we do: We restore the data link on the bench so the module can be read and programmed.
What you see: Dead key-on, or stalls when hot.
What's happening: Internal supply or cracked-joint failure.
What we do: We repair at the component level and thermal-cycle the module on the bench.
What you see: Several 5-volt sensor codes together that do not clear.
What's happening: The sensor supply regulator inside the ECM has failed.
What we do: We repair the supply and verify every sensor channel.
Don't see your exact symptom? Send it in anyway. We bench-test every unit before we tell you what's going on, and if we fix it the diagnostic cost you nothing.
Give us your engine serial prefix and we know which module you have.
| Arrangement | ECM generation / connector | Our bench | |
|---|---|---|---|
| 7AS | 3126B, ADEM III, 70-pin | 3-5 days | Start a 7AS repair → |
| 8YL | 3126B, ADEM III, 70-pin | 3-5 days | Start a 8YL repair → |
| 9SZ | 3126E, ADEM III, 70-pin | 3-5 days | Start a 9SZ repair → |
| CKM | 3126E, ADEM III, 70-pin | 3-5 days | Start a CKM repair → |
| HEP | 3126E, ADEM III, 70-pin | 3-5 days | Start a HEP repair → |
| 1WM | 3126, ADEM II, 40-pin | 15-30 days | Start a 1WM repair → |
ECM part numbers we see on the 3126: 157-3708, 162-7584, 192-7896, 179-4899, 206-2700 and Cat reman 10R-7986. If your label shows a different number, search it on the repair page.
Self-ship free, or add a prepaid UPS label. Drop-offs in Princeton, MN by appointment. Include your engine serial number.
70-pin units: you pay the repair price at checkout, and if we can't fix it you get a full refund. 1WM 40-pin units: $350 bench fee, credited the same way. We test it and tell you what failed, usually in 1-2 business days.
Whatever it needs to run right again. 70-pin units are 3 to 5 days on the bench. Need it sooner? Add rush priority at checkout and your ECM goes to the front of the line.
Programmed to your engine serial, tested here before it ships, lifetime warranty.
If yours is beyond repair, or the truck can't wait: remanufactured, bench-tested, programmed to your engine serial, 2-year warranty. Built to order unless the listing says In Stock; usually ships within 10 business days, often sooner.
On a 70-pin unit, you get a full refund when it is a normal failure we could not fix. We fix the large majority of the 70-pin ECMs that come in. The exceptions are when the ECM itself is the reason: a board that is cracked, burned, or eaten by water and corrosion, a proprietary chip that is no longer made, or damage from an earlier repair attempt. In those cases, and if your ECM tests good with nothing wrong, $150 covers the bench test, the written report and the return shipping, and we refund the rest. You can also put what you paid toward a tested exchange unit.
The 70-pin repair is $525 flat (sale through October 31, regularly $745), bench fee included, and 40-pin and 120-pin repairs are $745 flat. On 70-pin units you pay the repair price at checkout, before you ship it. If we can't fix a 70-pin, you get a full refund, unless the board itself is damaged beyond repair, a part is no longer made, or it tests good. Then $150 covers the bench test, the report and return shipping, and we refund the rest. 1WM 40-pin units start with a $350 bench fee that credits the same way.
70-pin units (7AS, 8YL, 9SZ, CKM, HEP) are 3 to 5 days on the bench right now, plus 1-3 days return shipping. The 40-pin 1WM runs 15 to 30 days.
Yes, to your engine serial, and bench-tested before it ships.
Yes. Remanufactured units for the 7AS, 8YL, 9SZ, CKM, HEP and 1WM programmed to your engine serial, 2-year warranty. Built to order unless the listing says In Stock.
Related: Cat 70-pin ECM problems & symptoms · All Cat ECM repair · C7 ECM repair · 3406E ECM repair · C12 ECM repair · Equipment ECM repair
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