L322 Range Rover System Description and Operation
STEERING
57-26
DESCRIPTION AND OPERATION
Unlocking of Steering Lock
If the battery voltage is 9V or less, the steering lock will be inoperative.
When a valid key is inserted and confirmed, the steering lock ECU activates the steering lock motor in the unlock
direction. Movement from the locked to the unlocked position is detected by the Hall sensor in the motor and sensed
by the steering lock ECU.
When the Hall sensor detects that the unlocked position has been reached, the ECU brakes the motor. The safety
release solenoid actuator is de-energised and its spring loaded pin drops into a recess in the locking bolt. This forms
a mechanical lock securing the locking bolt in the unlocked position preventing the steering lock from being applied
when the vehicle is being operated. A Hall sensor in the safety release solenoid actuator informs the steering lock
ECU of this condition. Once the unlocking procedure is successfully performed, the steering lock ECU de-energises
the steering lock motor.
Once the steering is successfully unlocked, the ignition switch lock disengages allowing the key to be turned to
positions II and III.
Detection of Locking Request
When the ignition key is turned to position 0, the ignition switch lock solenoid actuator remains active (unlocked) for
16 minutes. This function allows immediate restarting of the vehicle as long as the key is not removed from the ignition
switch. When the key is removed, the immobilisation ECU senses the removal and transmits a 'no valid key in lock'
message on the K bus. The steering lock ECU checks that the ignition switch position II or III outputs and the rotation
sensor are not active and initiates the steering locking process. This check ensures that the steering is not locked
when the vehicle may be being driven.
If the K bus is inoperative, locking of the steering column is prevented by the steering lock ECU. This is indicated to
the driver when attempting to start the vehicle through a delayed operation of the ignition switch lock solenoid actuator
preventing the key from being turned initially. The solenoid actuator is operated on a delay which will initially prevent
the key from being turned. The solenoid actuator will unlock and allow the key to turn on the second attempt. A defect
in the K bus is detected if no response from the immobilisation ECU is received after a 2.4 seconds period after the
'request immobilisation ECU status' is sent.
Locking of Steering Lock
The battery voltage must be greater than 10V and the vehicle must be stationary.
The ABS ECU transmits vehicle speed on a hardwired connection with the steering lock ECU. The steering lock ECU
uses the signal to determine when the vehicle has stopped.
When the key is removed and the steering lock ECU receives the 'no valid key in lock' message from the
immobilisation ECU, the steering lock motor is activated. The safety release solenoid actuator in the steering column
is energised, withdrawing the pin from the locking bolt. The Hall sensor in the solenoid actuator informs the steering
lock ECU that the lock is released.
The steering lock ECU then operates the steering lock motor in the lock direction. Movement from the unlocked to the
locked position is detected by the Hall sensor in the motor and sensed by the steering lock ECU. The safety release
solenoid actuator is de-energised and rests on the locking bolt.
