Duramax Module Services — by Engine Generation
LB7 · LLY · LBZ · LMM · LML · L5P — which module handles your fault, and which of them we repair
Almost every wasted Duramax module shipment we see comes from the same misunderstanding, and it is an entirely reasonable one: the truck has a dead miss or will not fire its injectors, the owner reads that the FICM is the usual suspect, and they pull a FICM off a truck that does not have one.
The injector drivers moved. On the LB7 and LLY they live in a separate Fuel Injection Control Module bolted to the engine. From the LBZ onward General Motors integrated them into the ECM itself. The symptom on the dashboard is identical; the module you need is not.
Two model years straddle that boundary and are worth extra care. A 2006 truck can be an LLY or an LBZ depending on build date, and a 2007 truck can be an LBZ or an LMM. Your VIN settles it in a minute — send it to us before you remove anything and we will tell you which module you are actually looking for, free.
Duramax generations
Find your engine, confirm where the drivers live, and go to the right service.
| Generation | Years | What's different | Module | Our service |
|---|---|---|---|---|
| LB7 | 2001-2004 | Separate FICM drives the injectors. Also the generation with the best-known injector failure reputation, which is why FICM-versus-injector diagnosis matters most here. | Fuel Injection Control Module (FICM) | Duramax LB7 / LLY FICM Repair$499.95 flat |
| LLY | 2004.5-2005 (into early-build 2006) | Still a separate FICM. Early-build 2006 trucks left the factory as LLY, so a 2006 model year alone does not tell you which architecture you have. | Fuel Injection Control Module (FICM) | Duramax LB7 / LLY FICM Repair$499.95 flat |
| LBZ | 2006-2007 | The change point. GM moved the injector drivers inside the ECM, so there is no separate FICM to repair and a driver fault is an ECM job. | E35 engine control module | Duramax E35 ECM Repair (2006-2007)$499.95 flat |
| LMM | 2007.5-2010 | The first Duramax generation with a diesel particulate filter, which adds a category of aftertreatment codes that are exhaust-hardware faults rather than module faults. | E35B engine control module | Duramax E35B ECM Repair (LMM)$499.95 flat |
| LML | 2011-2016 | Later-generation control hardware with DEF/SCR aftertreatment. Different from the E35 family in ways that matter to a bench repair. | Later-generation ECM | We do not currently offer a board-level repair for the LML ECM. Text us the module label and VIN and we will tell you honestly whether we can help — and if we cannot, we will say so rather than take the module. |
| L5P | 2017 onward | Current-generation control hardware. Newer, less accessible on the bench, and a higher bar to prove any repair holds up in service. | Current-generation ECM | Not a service we offer. We would rather tell you that plainly than take an L5P module and work it out on your truck. |
| Allison transmission | Across the range | The Allison automatic behind most Duramax trucks has its own transmission control module, with its own failure modes — solenoid drivers, supply sections, communication faults. | Allison transmission control module | Allison TCM repair is in development — we are validating a bench process and are not accepting these modules yet. Text us if you have one down and we will tell you where we stand. |
Separate FICM drives the injectors. Also the generation with the best-known injector failure reputation, which is why FICM-versus-injector diagnosis matters most here.
Module: Fuel Injection Control Module (FICM)
Still a separate FICM. Early-build 2006 trucks left the factory as LLY, so a 2006 model year alone does not tell you which architecture you have.
Module: Fuel Injection Control Module (FICM)
The change point. GM moved the injector drivers inside the ECM, so there is no separate FICM to repair and a driver fault is an ECM job.
Module: E35 engine control module
The first Duramax generation with a diesel particulate filter, which adds a category of aftertreatment codes that are exhaust-hardware faults rather than module faults.
Module: E35B engine control module
Later-generation control hardware with DEF/SCR aftertreatment. Different from the E35 family in ways that matter to a bench repair.
Module: Later-generation ECM
Current-generation control hardware. Newer, less accessible on the bench, and a higher bar to prove any repair holds up in service.
Module: Current-generation ECM
The Allison automatic behind most Duramax trucks has its own transmission control module, with its own failure modes — solenoid drivers, supply sections, communication faults.
Module: Allison transmission control module
Services in this category
Every one is a flat price, mail-in from any US state.
Duramax LB7 / LLY FICM Repair
No-start, dead miss, or a Duramax that runs rough on half its cylinders? On an LB7 or LLY the injector drivers live in a separate FICM — we repair that module on the bench and send your original back.
Duramax LB7 / LLY FICM Repair
No-start, dead miss, or a Duramax that runs rough on half its cylinders? On an LB7 or LLY the injector drivers live in a separate FICM — we repair that module on the bench and send your original back.
Duramax E35 ECM Repair (2006-2007)
No communication, a dead ECM, or injector-driver faults on a 2006-2007 Duramax? The E35 puts the injector drivers inside the ECM — we repair that board and return your original, VIN and calibration intact.
Duramax E35B ECM Repair (LMM)
LMM Duramax down with a dead ECM, no communication, or injector-driver faults? We repair the E35B at board level and send your original back with its calibration intact.
Frequently asked
Still not sure which module you need? Text us your VIN — replies in minutes.
How do I tell whether my truck has a separate FICM?
Why does it matter which one I have?
Is my dead miss the module or an injector?
Do you cover the LML and L5P?
Will you delete the DPF, EGR or DEF system?
Do you have a shop near me?
Also see
Not sure which module you need?
Send us your VIN and a photo of the module label. We confirm which one you have before you remove anything — free, usually within minutes, and we will tell you if the answer is that you do not need us.