IF UNIT IS NOT IN STOCK YOUR UNIT CAN BE SHIPPED IN FOR REPAIR AND RETURN (CONTACT CUSTOMER SERVICE FOR DETAILS) Power Control Module (PCM). Programmable control module. Module must be programmed to insure driveability & emission standards. SIERRA 2500 PICKUP 02-03 Elec Cont Unit (ECU); (left front under battery), diesel SIERRA 2500 PICKUP 04 Elec Cont Unit (ECU); (left front under battery), diesel, VIN "1" SIERRA 3500 PICKUP 02-03 Elec Cont Unit (ECU); (left front under battery), diesel SIERRA 3500 PICKUP 04 Elec Cont Unit (ECU); (left front under battery), diesel, VIN "1" SILVERADO 2500 PICKUP 02-03 Elec Cont Unit (ECU); (left front under battery), diesel SILVERADO 2500 PICKUP 04 Elec Cont Unit (ECU); (left front under battery), diesel, VIN "1" SILVERADO 3500 PICKUP 02-03 Elec Cont Unit (ECU); (left front under battery), diesel SILVERADO 3500 PICKUP 04 Elec Cont Unit (ECU); (left front under battery), diesel, VIN "1" PHOTO IS A STOCK PHOTO ALL UNITS ARE CLEANED, REBUILT AND TESTED TO SPECS BEFORE SHIPPING