For 1990-2009 cars

# CODE 45 CHECK ENG. LIGHT INOP. CANISTER CONTROL VALVE

IF THE CANISTER CONTROL VALVE ON A 5.0L OR 4.3L ENGINE SHOULD BECOME INOPERATIVE IT MAY SET A CODE NUMBER 45 OR MAY CAUSE A FULL LEAN COMMAND OF 55F DWELL. THIS VALVE CAN BE EASILY CHECKED BY APPLYING 15" OF VACUUM TO THE MANIFOLD VACUUM PORT. WITH VACUUM APPLIED YOU SHOULD NOT BE ABLE TO BLOW THROUGH THE CARBURETOR BOWL VENT NIPPLE ON THE VALVE, IF YOU CAN THE VALVE MUST BE REPLACED.

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.