GM

The naturally aspirated LCV combines direct injection and dual cam timing in a compact four-cylinder. Pickup and crossover ratings differ, and the engine should not be confused with GM’s turbocharged 2.5L.

The LFX packages GM’s direct-injected 3.6L for cars, crossovers and midsize pickups. Output and electronics vary by installation: a Terrain and a Canyon can share LFX on the RPO label without sharing an ECM family.

The LML delivers 397 hp and 765 lb-ft in HD pickups, with high-pressure common-rail injection and SCR using diesel exhaust fluid. Correct fuel-system diagnosis matters: contamination can turn a pump repair into a much larger job.

The LF1 and flex-fuel LFW bring DOHC V6 refinement to the early Terrain and Equinox. The RPO changed before the body did: Terrain uses LF1 in 2010 and LFW in 2011–2012.

The LAF and flex-fuel LEA power the first-generation Terrain and Equinox. Direct injection and variable cam timing improve efficiency, but oil consumption and the timing system deserve particular attention on these engines.

The LGH puts Duramax torque to work in vans and selected chassis-cab trucks. Its commercial ratings, transmission pairing and calibration differ from an LML pickup, even though the engines share their basic 6.6L architecture.

Direct injection gives the LLT-powered Acadia more power without increasing displacement. It remained in the original-body crossover for years, including the 2017 Acadia Limited, so body generation matters as much as model year.

These engines pair a 6.0L V8 with GM’s two-mode hybrid transmission. The system can blend electric drive, engine torque and cylinder deactivation; engine diagnosis therefore includes the hybrid powertrain rather than a standalone ECM.

The 3.7L LLR brings 242 hp to GM’s midsize pickups and H3. It retains the Atlas five-cylinder character, with port injection and exhaust cam phasing; the production-year controller split matters when selecting replacement electronics.

The LLV enlarges GM’s Atlas four-cylinder to 2.9L. Its larger bore brings 185 hp, while the controller transition during production is important for parts, diagnosis and calibration compatibility.