Aftermarket (Add-On) Electrical and Vacuum Equipment

Aftermarket (Add-on) Electrical and Vacuum Equipment is defined as any equipment installed on a vehicle after leaving the factory where the vehicle was originally assembled that connects, in any way, to the vehicles electrical or vacuum systems. These accessories may lead to an emission related OBD II failure while in use, but do not fail when the accessories are not in use. Refer to Checking Aftermarket Accessories in Diagrams. If a DTC is determined to be intermittent, and the tests in this system do not reveal a problem, refer to Powertrain Control Module Diagnosis. No allowances have been made in the design of this vehicle for this type of equipment. Therefore, addition of aftermarket equipment must be done with the utmost care for the vehicle.