Option code L5P · Engine
6.6L Duramax Turbo-Diesel V8
The HD diesel — verifying L5P vs the L8T gas 6.6 is the first question on any used HD truck.
Documented on
- Silverado HD, Sierra HD (2017+)
How to confirm it on a real car
GM RPO records factory equipment on the Service Parts Identification (SPID) label in the glovebox. Stickers go missing and cars get modified, so the ground truth for any specific VIN is the factory build record: every option code the car was born with, including L5P if it was ordered.
Was L5P on your car's original build?
The CarWhere build sheet decodes any GM VIN into its full factory record — every option code, the original paint, trim and equipment, as built. $9.99, instant.
More engine codes
Independent reference; not affiliated with GM RPO. Applicability varies by market and model year.