External Controls
External ControlsCOMPONENT LOCATION
INTRODUCTION
The Transmission Control Module (TCM) contains software to provide operation as a semi-automatic 'Jaguar Sequential Shift' transmission.
The TCM allows the transmission to be operated as a conventional automatic unit by selecting P, R, N, D on the selector lever. In this mode, the selector lever is linked, via the selector cable, to the transmission to provide a mechanical interface.
Movement of the selector lever across the 'L' gate to the 'S' position is sensed by a Hall effect proximity sensor located within the selector mechanism assembly, and puts the transmission into electronic 'Sport' mode.
Two gear change 'paddle' switches are fitted at the rear of the steering wheel and allow the driver to operate the transmission as a semi-automatic manual gearbox using the Jaguar Sequential Shift feature.
Selector Lever
The transmission selector assembly is located in a central position in the floor console. The assembly is attached to a moulding in the floor console with four screws.
A park switch is located to the right of the lever and is operated when the lever is moved to the R Park position. The lever is located in a slot in a rotary disc. The disc rotates with movement of the lever in the forward or back directions. The disk movement is detected by Hall sensors located on the selector PCB which correspond with the different selector positions.
Movement of the selector lever is passed to the transmission Mechatronic valve block via a lever located on the side of the transmission casing. The lever, in turn, moves a manually operated selector valve within the transmission valve block.
An interlock solenoid is located in the selector lever assembly. When energized, the solenoid engages an interlock lever preventing the selector lever from being moved. When the footbrake is applied, a signal from the brake switch deenergises the solenoid allowing the selector lever to be moved from the R or 'N' position. This prevents the selector from being moved to the 'L' or 'R' position unintentionally and the application of the brakes also prevents the vehicle 'creeping' when the gear is engaged.
If electrical power to the selector lever is lost, the selector lever will be locked in the 'N' or 'P' position by the shift interlock solenoid if moved from the 'D' position. The selector lever will remain locked until electrical power to the selector lever is restored. There is no emergency interlock solenoid release mechanism on the selector lever.
Selections made using the selector lever are passed to the TCM in high speed Controller Area Network (CAN) bus messages. The park switch is hardwired to the instrument cluster and the Central Junction Box (CJB).
Paddle Switches
Each paddle switch has 3 connections; ground, illumination Pulse Width Modulation (PWM) supply and switch signal.
Pulling the LH downshift paddle (-) provides down changes and pulling the RH upshift (+) paddle provides up changes. The first operation of either paddle, after Sport mode is selected, puts the transmission into permanent manual 'Jaguar Sequential Shift' mode. Movement of the selector lever back to the 'D' position, returns the transmission to conventional automatic operation. To reselect Sport mode from Manual mode, the selector lever must be first moved to the 'D' position and then returned to the 'S' position.
Temporary operation of manual mode can also be operated with the selector lever in the 'D' position. Operation of either the upshift or downshift paddles activates the manual mode operation. The current selected gear will displayed in the instrument cluster message center. If continued use of manual mode is required, move the selector lever to the 'S' position.
With the selector lever in the 'D' position, temporary manual mode will be maintained whilst the driver is accelerating, decelerating, cornering or continuing to request shifts via the paddles. The transmission will revert to automatic operation after a short period of driving at steady speed. Alternatively the RH upshift (+) paddle may be held for approximately one second to return directly to automatic operation in U.
PRINCIPLES OF OPERATION
Selector Lever
The selector lever is located in a slot in the rotary disc which rotates with movement of the lever in the forward or back directions. The disc movement positions magnets located on the disc which are detected by Hall sensors located on the selector PCB which correspond with the different selector positions. The Hall sensors produce a signal relative to the lever position which is passed as a high speed CAN bus message to other system modules.
Paddle Switches
When the switch is operated, a ground for the switch contacts is completed via a resistor. The completed ground signal is passed via a hardwired connection to the steering wheel module. The module converts the switch signal into a Local Interconnect Network (LIN) bus message which in turn is passed to the instrument cluster, via the steering wheel clockspring. The instrument cluster converts the LIN message into a high speed CAN bus message which is broadcast to the TCM and other system modules.