sl, sls and sle are trim levels. GMC offers three trim levels for the Sonoma. The SL is the base model, while the SLS provides the mid-range option. For those looking for a fully equipped Sonoma, GMC offers the SLE trim level. The earlier versions of the Sonoma compact trucks also offer plenty of exterior paint choices and interior options, such as vinyl in the lower trim levels or cloth for the upgraded trim levels
Sl SLS and SLE is a VOG (Vehicle Ordering Guide) trim code..and the individual letters mean nothing. 'SL' trims are for GMC Vehicles like Acadias, Sierras, Canyons, Yukons, Terrain and Sonomas. The letters don't stand for anything.
The second-generation GMC Sonoma was produced from 1994-2004. It was offered in regular, extended and (later on) crew cab bodies with short and long beds. Engine choices included a 2.2-liter four-cylinder (118 horsepower), a 4.3-liter V6 (165 hp) and the Vortec 4.3-liter V6 (195 hp). All three engines were available with either five-speed manual or four-speed automatic transmissions, and four-wheel drive was optional.
Trim levels typically consisted of base SL, midlevel SLS and luxury SLE. The SL was a stripper with vinyl bench seating and the SLS added cloth upholstery, air-conditioning, cruise control, foglights and alloy wheels. The SLE added chrome exterior trim, more luxurious seating and full power accessories.
I found that on Edmunds.
Read more: http://www.automotive.com/gmc/sonoma/t3-13-3/#ixzz3NOYkBB5o
GM Archives have been updated and 2000 was dropped (in response to other answer). https://archives.media.gm.com/us/gmc/en/product_services/r_cars/2001/01sonoma.html
OH yeah...I answered this (years later) for posterity because I own a 2000 GMC Sonoma SLS.
