Transmission Control Switch (TCS)

Courtesy of JAGUAR LAND ROVER NORTH AMERICA, LLC

NOTE: The Transmission Control Switch (TCS) is not a serviceable component. Repairs to the TCS must not be attempted. The TCS must be replaced as an assembly.

The Transmission Control Switch (TCS) is a rotary switch installed in the floor console. The TCS controls the driver transmission selections.

Rotation of the TCS to any of the five positions outputs a signal to the TCM. The TCM senses the signals via the High Speed (HS) Controller Area Network (CAN) powertrain systems bus. The TCM then reacts according to the selected TCS position. The TCS uses Hall effect sensors to determine the position of the switch.

The TCS is a fully electronic rotary transmission selector with no mechanical connection to the transmission.

The TCM allows the transmission to be operated as a conventional automatic unit by rotating the TCS to the Park (P), Reverse (R), Neutral (N) and Drive (D) positions. By depressing the TCS and rotating clockwise from the 'D' position, Sport(S) mode can be selected.

The TCS rotary switch rises from the floor console once the engine is running.

The engine can be stopped with the TCS in any position. Once the engine is stopped the TCS will automatically reset to the P position and the transmission park lock will be engaged. The only exception is if the TCS is moved to the 'N' position when the engine is stopped.

When the engine is stopped with the TCS in any position other than 'N', the TCS retracts into the floor console.

If the TCS is in position 'N' when the engine is stopped, it remains in the raised position for up to 10 minutes and the transmission remains in neutral. This is to enable the vehicle to be stopped in a drive through car wash for example. After 10 minutes the TCS automatically retracts, the TCS will automatically reset to the P position and the transmission park lock will be engaged. The TCS also retracts if 'P' is selected within the 10 minute period.

NOTE: When P is selected the Electric Park Brake (EPB) is automatically applied. The EPB is also automatically applied when the engine is stopped. The EPB automatic application can be overridden by holding the EPB switch in the release position and within five seconds stop the engine. Hold the EPB switch for a further 2 seconds after the engine has stopped. This allows the vehicle to be in the N position with the EPB not applied

To prevent this automatic operation, when the vehicle is stationary, press and hold the EPB switch in the release position. Within 5 seconds, switch off the ignition and continue to hold the EPB switch for a further 2 seconds.

The TCS strategy is for the TCS to remain retracted and locked until the foot brake is applied and the engine is running (power mode 7), at which point the TCS will rise. Under a low primary battery voltage condition, the TCS may be slow to rise or may fail to rise from its docked position. Once the engine is running, the retracted TCS can still be rotated to select gear positions other than 'P', but this must only be done in exceptional or emergency situations.

CAUTION: If the TCS fails to rise, it must only be rotated under exceptional circumstances. Once rotated the TCS may become mechanically locked and following an engine stop will require replacement

If the TCS fails to rise due to a low primary battery voltage condition, do not attempt to rotate the TCS to make a gear selection. Allow sufficient time for the battery to charge, then stop and restart the engine. The TCS will rise automatically within a short time.

If electrical power to the TCS is lost, the TCS will not rise from the floor console when the engine is started. The retracted TCS will not rotate without electrical power.

The TCS contains an internal interlock solenoid to prevent the TCS from being rotated when the engine is not running.

The Sport(S) position allows the TCM to operate the transmission using the semi-automatic CommandShift mode. Gear selections are sensed by the TCM when the driver operates the steering wheel paddle switches. Once the TCS position is confirmed, the TCM outputs appropriate information on the FlexRay systems bus to the Body Control Module/Gateway Module (BCM/GWM). The information is received by the Instrument Cluster (IC) to display the gear selection information in the message center.

The steering wheel paddle switches can also be used on a temporary basis. When the TCS is in the 'D' position, operation of the paddle switches will override the automatic gear selection if required.