Principles of Operation

PRINCIPLES OF OPERATION

Smart Junction Box (SJB)
The SJB is on the international standards organization (ISO) 9141 communications network. The SJB is installed on all vehicles. The SJB is a combination of a multifunction control module and a power junction box. The SJB functions control multiple systems which include:
- remote keyless entry (RKE)
- illuminated entry and interior lamps
- power door locks
- windshield wipers
- daytime running lamps
- battery saver
- accessory delay
- power windows

Powertrain Control Module (PCM)
The PCM is on the standard corporate protocol (SCP) communications network. If one of the bus wires becomes shorted to ground or voltage, or if some but not all termination resistors are lost, communications can continue. Check circuits 915 (PK/LB) and 914 (TN/OG) between the PCM C175 and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open circuit in the SCP communications network, damage to the DLC C251, damage to the PCM C175, or a problem in the in-line connector.

Restraints Control Module (RCM)
The RCM is on the ISO 9141 communications network. The RCM controls the deployment of the air bags based on sensor input.

Instrument Cluster
The instrument cluster is the only module on the controller area network (CAN). It is an analog face cluster with a digital odometer. The instrument cluster displays a variety of information.

Anti-Lock Brake System (ABS) Module
The ABS module is on the ISO 9141 communications network. The ABS module controls the brake pressure to the 4 wheels to keep the vehicle under control while braking.

Four-Wheel Drive (4WD) Control Module
The 4WD control module (if equipped) is on the ISO 9141 communications network. The 4WD control module controls the four wheel drive for the vehicle.