System Description And Functional Operation: Notes

The JR body system consists of a combination of modules that communicate over the PCI bus (Programmable Communication Interface multiplex system). Through the PCI bus, information about the operation of vehicle components and circuits is relayed quickly to the appropriate modules. All modules receive all the information transmitted on the bus even though a module may not require all information to perform its function. It will only respond to messages "addressed" to it through a binary coding process. This method of data transmission significantly reduces the complexity of the wiring in the vehicle and the size of wiring harnesses. All of the information about the functioning of all the systems is organized, controlled and communicated by the PCI bus, which is described in VEHICLE COMMUNICATION .

Always begin by reading the diagnostic trouble codes using the DRBIII®. Next, look for the symptom in DIAGNOSTIC INFORMATION AND PROCEDURES . This will direct you to the specific tests that must be performed.

NOTE: If the Powertrain Control Module has been changed and the correct VIN and mileage have not been programmed, a DTC will be set in the Airbag module. In addition, if the vehicle is equipped with a Sentry Key Immobilizer Module (SKIM), Secret Key data must be updated to enable starting. Refer to the POWERTRAIN DIAGNOSTIC PROCEDURES article for more information. Erase codes in all modules.