GM Duramax 3.0L LM2: Specs, Engine Codes, Controllers & Maintenance
Engine Information · GM · Duramax · inline-six · LM2
Duramax 3.0L LM2
The LM2’s smooth inline-six brings diesel torque to light-duty pickups and full-size SUVs. Two controller generations overlap its production, while rear-mounted service components make accurate diagnosis especially valuable.
Engine construction
| Specification | Details |
|---|---|
| Capacity / layout | 3.0L · inline-six |
| Bore × stroke | 84 × 90 mm |
| Construction | Aluminum block and head |
| Valve gear | DOHC · 24 valves · variable timing |
| Compression / fuel | 15.0:1 · common-rail direct injection |
| Induction / emissions | Turbocharged · EGR / DPF / SCR |
Codes & output
| RPO / version | Power / torque | Key difference |
|---|---|---|
| LM2 | 277 hp / 460 lb-ft | North American factory rating |
SAE horsepower; torque in lb-ft. Ratings are for the stated application and fuel, rather than every vehicle with this RPO.
Vehicles & model years
| Brand | Model | Model years | Platform / chassis | Engine RPO |
|---|---|---|---|---|
| GMC / Chevrolet | Sierra / Silverado 1500 | 2020–2022 | T1XX | LM2 |
| GMC / Chevrolet | Yukon / Yukon XL; Tahoe / Suburban | 2021–2024 | T1XX SUV | LM2 |
| Cadillac | Escalade / Escalade ESV | 2021–2024 | T1XX SUV | LM2 |
U.S. and Canadian applications within the 2005–2026 matrix scope. Engine availability depends on trim, build date and emissions certification.
Engine controllers
| Application / revision | ECM or PCM | Identification & function |
|---|---|---|
| Early non-Global B pickups | GM E46 ECM | Typically 2020–2022 original-body/limited trucks; verify build |
| Global B applications | GM E66 ECM | 2021+ SUVs and refreshed 2022 pickups; electrical architecture determines the correct workflow |
| Control functions | Injection, boost and emissions coordination | Read ECM service ID, calibration ID and full module fault set before programming |
Identify the module from its service number, operating-system ID and VIN. The ECM/PCM and transmission controller have separate calibrations on many applications; a matching RPO alone does not make a replacement module plug-and-play.
Common issues & maintenance
- Rear oil leaks / P06DDGM 22-NA-022 links specified rear-cover oil leaks and oil-pump-control faults to diagnostic checks. Locate the leak and test the control circuit before assuming the rear crankshaft seal is the cause.
- Aftertreatment and fuel faultsDEF, exhaust-sensor and fuel-system warnings can reduce performance. Use pressure, dosing and sensor data to identify the failed component.
- Rear oil-pump drive beltThis is a scheduled service item with a model-year interval, not a lifetime component. Budget for access-intensive replacement and confirm the current maintenance schedule.
Keep it healthy. Use the prescribed dexosD diesel oil and fuel-filter schedule. Keep oil level correct, investigate leaks early and allow normal regeneration to finish when driving conditions permit.
References & technical sources
| Source | Reference |
|---|---|
| GM applications & RPO diagnostic matrices | View source |
| GM TechLink 2026 U.S./Canada oil chart | View source |
| 2022 GMC LM2 technical specifications | View source |
| HP Tuners E46/E90/E93 identification | View source |
| HP Tuners E66 application table | View source |
| GM rear-oil-leak diagnostic bulletin | View source |
