GM Gen IV Vortec 4.8L V8 LY2 & L20: Specs, Engine Codes, Controllers & Maintenance
Engine Information · GM · Small-block · Gen IV
Gen IV Vortec 4.8L V8 LY2 & L20
These 4.8L V8s keep the simple eight-cylinder character of GM’s smaller truck engines. L20 adds variable cam timing and flex-fuel capability, so the RPO matters even when displacement and appearance match.
Engine construction
| Specification | Details |
|---|---|
| Capacity / layout | 4.8L · 90° V8 |
| Valve gear | OHV · 16 valves · chain-driven camshaft |
| Fuel / induction | Port injection · naturally aspirated |
| Identification | Check RPO, block casting, AFM and VVT equipment |
| Construction | Iron block · aluminum heads |
| Cylinder deactivation | No factory AFM on LY2 / L20 |
Codes & output
| RPO / version | Power / torque | Key difference |
|---|---|---|
| LY2 | 295 hp / 305 lb-ft | Typical pickup rating; fixed cam timing |
| L20 | 302 hp / 305 lb-ft | Typical pickup rating; VVT / flex-fuel |
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 | 2007–2009 | GMT900 | LY2 |
| GMC / Chevrolet | Sierra / Silverado 1500 | 2010–2013 | GMT900 | L20 |
| GMC / Chevrolet | Yukon / Tahoe | 2007–2009 | GMT900 | LY2 |
| GMC / Chevrolet | Savana / Express | 2007–2009; 2010–2017 | GMT610 | LY2; L20 |
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 |
|---|---|---|
| Gen IV 4.8L applications | GM E38 ECM | Fuel / spark / throttle; L20 calibration also manages cam timing and flex-fuel strategy |
| Automatic transmission | Separate GM TCM | Controller type follows gearbox and build; engine and transmission files must match |
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
- Throttle / sensor faultsReduced-power messages can come from throttle-position or wiring faults. Verify scan data and the applicable service bulletin before replacing the ECM.
- Oil-pressure / sealingCheck actual pressure, oil level, pickup sealing and external leaks. A pressure-sensor fault and genuinely low pressure need different repairs.
- Ignition / fuel deliveryInvestigate rough running with cylinder misfire counts, ignition tests and fuel trims. AFM-lifter diagnosis does not apply to these non-AFM RPOs.
Keep it healthy. Use the oil grade and specification in the model-year owner’s manual. Check the dipstick between services; towing, idling and short trips change oil-life demands. Repair coolant leaks promptly, keep the cooling stack clear and investigate a new tick or misfire before it damages the camshaft or catalyst.
References & technical sources
| Source | Reference |
|---|---|
| GM applications & RPO diagnostic matrices | View source |
| EFILive GM gasoline controller families | View source |
| GM V8 oil-consumption diagnostic bulletin | View source |
| GM throttle-position coverage bulletin | View source |
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