SMU - SECTION 5 - EVAPORATIVE EMISSION (EVAP) CONTROL. GMC Truck GMC G Van 1993

SUBJECT: SERVICE MANUAL UPDATE-SECTION 5-EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM-REVISED GENERAL AND CIRCUIT DESCRIPTION TEXT

MODELS: 1993-95 CHEVROLET AND GMC TRUCK G, C/K, M/L, S/T, P3, P/G MODELS WITH 4.3L, 5.0L, 5.7L, 7.4L ENGINES (VINS W, Z, H, K, N - RPOS L35, LB4, L03, L05, L19)

THIS BULLETIN IS BEING ISSUED TO REVISE THE GENERAL DESCRIPTION AND CIRCUIT DESCRIPTION OF THE CANISTER PURGE SOLENOID CHECK IN SECTION 5 OF THE FOLLOWING SERVICE MANUALS:

* 1993 LIGHT DUTY TRUCK FUEL EMISSIONS - PAGES 5-3 AND 5-4 * 1994-95 G VAN, C/K, M/L, P3 AND P/G DRIVEABILITY, EMISSIONS AND ELECTRICAL DIAGNOSIS MANUAL - PAGES 5-2 AND 5-4 * 1994 S/T DRIVEABILITY, EMISSIONS AND ELECTRICAL - PAGE 5-4 * 1995 S/T DRIVEABILITY, EMISSIONS AND ELECTRICAL -PAGES 5-8 AND 5-10

THIS HAS BEEN REVISED TO READ:

GENERAL DESCRIPTION: THIS EVAP SYSTEM USES AN ELECTRICALLY CONTROLLED SOLENOID TO PURGE FUEL VAPOR FROM THE EVAP CANISTER TO THE INTAKE MANIFOLD. THE CONTROL MODULE CYCLES THE SOLENOID, ONCE THE ENGINE COOLANT HAS REACHED NORMAL OPERATING TEMPERATURE.

CIRCUIT DESCRIPTION: B+ IS APPLIED TO THE EVAP CANISTER PURGE SOLENOID WHEN THE IGNITION KEY IS TURNED "ON". ONCE THE ENGINE COOLANT HAS REACHED NORMAL OPERATING TEMPERATURE, THE CONTROL MODULE GROUNDS THE EVAP CANISTER PURGE CONTROL CIRCUIT. THE PURGE SOLENOID WILL OPEN, ALLOWING THE FUEL VAPORS FROM THE VAPOR CANISTER TO BE DIRECTED TO THE INTAKE MANIFOLD.

FIGURES: 00 ATTACHMENTS: 00

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.