Principles of Operation

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2008 Jaguar S-Type, 2007 Jaguar S-Type, 2006 Jaguar S-Type, 2005 Jaguar S-Type, and 2004 Jaguar S-Type. However, it is still accessible from the selected car via links, so may be relevant.

The vehicle has four module communication networks. Only three of these networks are connected to the diagnostic connector. The standard corporate protocol (SCP) and controller area network (CAN), which are an unshielded twisted pair cable: data bus plus and data bus minus and the International Standard Organization (ISO) 9141 communication network, which is a single wire network. The digital data bus (D2B), which is a fibre optic ring network can only be accessed through the SCP network. The SCP, CAN and ISO networks can be connected to the Jaguar Approved Diagnostic System by one connector called the diagnostic connector. This makes troubleshooting these systems easier by allowing one smart tester to be able to diagnose and control any module on the three networks from one connector. Diagnosis of the D2B network is through the entertainment system audio unit. The diagnostic connector is located on the driver's side, under the instrument panel.

The ISO 9141 communications network does not permit inter-module communications. When the Jaguar Approved Diagnostic System communicates to modules on the ISO 9141 communication network, the diagnostic system must ask for all information; the modules initiate communications.

The SCP communication network remains operational even with severing of one of the bus wires. Communications will also continue if one of the bus wires is shorted to ground or battery positive voltage (B+), or if some, but not all, termination resistors are lost.

Unlike the SCP communication network, the ISO 9141 communication network will not function if the wire is shorted to ground or battery positive voltage (B+). Also, if one of the modules on the ISO 9141 network loses power or shorts internally, communication to that module will fail.

The anti-lock brake system (ABS), traction control (TC) and dynamic stability control (DSC) module is connected to the CAN communication network. It controls the brake pressure to the four wheels to keep the vehicle under control while braking. This module also communicates with the yaw and steering wheel angle sensors to help in sensing a loss of vehicle control. For additional information, refer to Anti-Lock Control - Stability Assist .

The entertainment system audio unit is connected to the SCP communication network and also to the D2B network. The D2B communicates with the compact disc and the cellular phone transceiver and the amplifier. For additional information on the compact disc, refer to Information and Entertainment System - General Information . For additional information on the cellular phone, refer to Cellular Phone .

The climate control module is connected to the CAN communication network. The climate control assembly automatically maintains a selected temperature for the interior of the vehicle. For additional information, refer to Climate Control System - General Information .

The instrument cluster (IC) is connected to the CAN and SCP communication networks. The instrument cluster displays information received on the SCP including speedometer, odometer, fuel, and message center warnings. The instrument cluster displays information received on the CAN including ABS, air conditioning, transmission and engine condition. The instrument cluster also controls the passive anti-theft system (PATS), and the steering column lock actuator (SCLA). For instrument cluster operation, refer to Instrument Cluster and Panel Illumination . For PATS operation, refer to Anti-Theft - Active or Anti-Theft - Passive . For the steering column lock actuator operation, refer to Steering Column . The instrument cluster, steering column lock actuator and the engine control module (ECM) are all configured together. Replacing one requires the others to be re-configured.

The front electronic module (FEM) is connected to the SCP communication network. The FEM controls both interior and front exterior lighting, hazard and indicator functions, adjustable pedals, levels (low brake/washer fluid, low oil pressure) and memory functions. For additional information Refer to Multifunction Electronic Modules .

The ECM is connected to both the CAN and ISO 9141 communication networks. The ECM controls the engine performance, electronic ignition, emission controls, speed control, and on board diagnostics. For additional information Refer to Electronic Engine Controls . Or Refer to Electronic Engine Controls .

The vehicle emergency message system module (VEMS) is connected to the D2B communication network. The module allows a user to request emergency assistance (police, ambulance, fire, recovery) or directions to a desired location at the touch of a button. Also, if any of the vehicle's airbags are deployed while the VEMS system is powered ON, the system automatically issues a call for emergency assistance. For additional information, refer to Telematics .

The restraint control module (RCM) is connected to the ISO 9141 communication network. The RCM controls the deployment of the air bags based on sensor input. For additional information; Refer to Supplemental Restraint System .

The voice activated control module (VACM) is connected to the D2B communication network. This allows the user to select functions by giving a nine voice command. The VACM sends the command information by D2B to the correct module or audio unit.

The navigation control (NAV) module is connected to the SCP network. The navigation control module receives inputs from the GPS antenna and various other sensors. For additional information, refer to Navigation System .

The driver door module (DDM) is connected to the SCP communication network. The module controls many functions including power windows, power locks, and keyless remote entry. The DDM also communicates with the driver seat module (DSM) to control power seat and mirror memory. For additional information, refer to Multifunction Electronic Modules .

The driver seat module (DSM) is connected to the SCP communication network. The DSM controls the driver power seat. The module also communicates with the DDM to control the driver seat memory and both outside memory mirror functions. For additional information, refer to Multifunction Electronic Modules .

The rear electronic control module (REM) is connected to the SCP network. The REM controls the exterior rear lamps, the heated rear window, inertia switch operation, trailer functionality, fuel pump driver circuit and luggage compartment lid. For additional information Refer to Multifunction Electronic Modules .

The steering column lock actuator (SCLA) is connected to the SCP communication network. The module controls locking of the steering column and is only equipped on vehicles with manual transmissions. It is controlled by the instrument cluster. For additional information Refer to Steering Column Switches .

The adaptive damping module is connected to the SCP communication network. The module calculates the movement of the vehicle and adjusts the suspension accordingly. For additional information, refer to Vehicle Dynamic Suspension .

The electronic park brake (EPB) module is connected to the SCP communication network. The electronic park brake module controls the electrical functions of the park brake system. For additional information, refer to Parking Brake and Actuation .

The high intensity discharge (HID) headlamp module is connected to the ISO 9141 communication network and also the CAN communication network. The high intensity discharge headlamp module regulates the lamp output. For additional information Refer to Exterior Lighting .

The transmission selector lever (JGM) is connected to the CAN communication network. The transmission selector lever communicates with the transmission control module (TCM) and also perform its own internal fault monitoring. For additional information, refer to Automatic Transmission/Transaxle External Controls .

The transmission control module (TCM) is connected to the CAN communication network. The TCM controls the automatic gearbox control solenoids as well as communicating with other powertrain components on the CAN communication network. The TCM also provides for legislated diagnostics. For additional information, refer to Automatic Transmission/Transaxle .

The reverse parking aid module is connected to the ISO 9141 communication network. The reverse parking aid module controls the electrical components of the parking aid system.