Technical Training
DWA
The DWA Anti-theft Warning System is a dealer installed option on the MINI.
Purpose of the System
The anti-theft warning system (DWA) monitors the contacts on the doors, tailgate and bonnet as well as the status of the ignition switch terminals, tilt sensor and the interior protection. The DWA system is controlled by the Body Control Module (BC1), which like the auxiliary powered siren is installed in a place that is difficult to access, this prevents interference with alarm operation.
System Components
In addition to the BC1 the DWA system consists of the following components:
- Door, Hood and Tailgate Switches
- DWA LED
- Tilt Sensor
- UIS Sensor
- Auxiliary Powered Siren
Door Switches
The BC1 uses input from the same door position and lock/unlock micro switches used for door status and position by the Central Lock System.
Hood Switch
The hood switch is a micro switch situated in the hood opening mechanism on the left-hand side of the engine compartment (viewed from the front bumper).
Tailgate Switch
Tailgate position status is received by the BC1 from the tailgate release actuator.
Tilt Sensor
The tilt sensor is situated on the left side of the luggage compartment. Its purpose is to measure the vehicle parked angle when the DWA is armed.
The tilt sensor wire uses three wires:
- DWA 12v - supply voltage from the BC1 to the tilt sensor.
- NG - switched ground output to the BC1
- KL 31 - ground
DWA LED
The DWA LED located on the wiper stalk flashes to provide information about DWA status.
The LED had 4 flash patterns:
Confidence Flash
All the time the alarm is armed the LED will flash on for 10ms with a 1 second delay until the next flash
Volumetric Flash
Pressing the remote or locking the car one time activates Volumetric Arming, the monitoring of all contacts plus the tilt and UIS sensor. For 10 seconds after Volumetric arming the LED will flash rapidly (8hz), 10ms on with only 125ms between flashes. After the 10 second period the LED will flash in the Confidence Mode.
Perimeter Flash
Pressing the lock button twice in two seconds arms the DWA in the Perimeter mode, using only door, hood and tailgate contacts, the tilt and UIS are switched off. For 10 seconds after Perimeter arming the LED will flash rapidly, 10ms on with 125ms between flashes for 1 second, then a 1 second pause, followed by the rapid flashing. At the end of this 10 second sequence the LED will flash in the Confidence Mode.
Tamper Flash
If the alarm has been triggered, the Tamper Flash pattern will be given during disarming. The tamper flash pattern is a slow 200ms on 200ms off pattern.
UIS Sensor
The UIS Sensor (Ultrasonic) is mounted at the rear of the vehicle on the headliner. Every time the DWA is armed the UIS sensor adapts to whatever objects are stationary in the interior.
The sensor emits ultra sonic waves in a programmed timed cycle and receives echoes of the returning waves. The UIS amplifies the returned sound wave signals and compares them with the transmitted waves. Similar echoes received indicate no movement is detected. Inconsistent or altered returned signals indicate motion in the interior. When motion is detected the UIS changes to a constant rather than timed program and compares returning echoes. If inconsistencies are still present the BC1 is notified of the motion.
Auxiliary Powered Siren
The auxiliary powered siren is situated in the left hand rear of the engine bay (viewed from the front bumper). The siren contains electronic circuitry for producing the warning tone when the alarm is triggered. The siren also contains a rechargeable battery that is used to power the siren when the alarm is triggered.
In the armed state the auxiliary powered siren is armed by the BC1 holding the arming line to ground, if the power to the BC1 is lost the arm line will be released, which will send power to the auxiliary powered siren. This will cause the auxiliary powered siren to go into its internal triggering sequence.
Principle of Operation
Arming
The following two actions are both regarded as arm actions:
- Pressing the lock button on the remote
- Turning the door lock to the lock position.
The DWA will be Volumetric armed by the first arm action. Volumetric arming is confirmed by rapid flashing of the DWA LED.
Two identical arming actions occurring sequentially within two seconds will put the DWA into Perimeter mode. Perimeter arming is confirmed by blinking of the DWA LED.
Any further arm actions within two seconds will have no effect on the DWA. Following the two seconds, the DWA will ignore any key arm actions. However any further remote arm actions will turn on the interior light for a period of ten seconds. This feature provides a way of locating the car in a large parking lot.
The BC1 will briefly flash the turn signals three times when the car is locked from the outside and the DWA is armed.
Arming with a Contact Open
If the DWA is armed with the passenger door, tailgate or bonnet open the BC1 will not flash the LED in the relevant mode for the first 10-seconds after arming - this is to indicate to the owner a contact is not closed - after this the LED will flash in confidence mode. The BC1 will also not activate the interior protection and tilt sensor. If the contact is closed after the DWA is armed the LED will flash for 10-seconds in the relevant mode.
Arming with a Window Open
The BC1 uses the current monitoring function for the windows to identify whether the window is in the closed position. If the window is identified as not closed the BC1 will deactivate just the interior protection system.
Disarming
The DWA is disarmed by pressing the unlock button on the remote, turning the door lock to the unlock position or through reading the transponder by turning the ignition lock to the terminal R or 15 position. The DWA will signal that it has been successfully disarmed when the DWA LED stops flashing in confidence mode. If the DWA is triggered then disarming will silence the alarm sounder.
If the DWA has been triggered or is triggering then when it is disarmed the DWA LED will alert the driver to this fact by flashing in Tamper mode. This tamper flash will be terminated when terminal R or terminal 15 goes high or if the alarm is armed again. If the disarm request is made when the DWA is triggering then disarming the trigger cycle will be terminated and the auxiliary powered siren will be silenced and the hazard warning lamps turned off.
Alarm Triggering
The DWA is triggered when any one of the following states are detected:
- Ignition ON (When alarm system is not disarmed)
- Hood Open
- Tailgate Open
- Driver's Door Open
- Passenger Door Open
- Tilt: Sensor Triggered (When Armed)
- UIS Triggered (When Armed)
When the DWA is triggered the auxiliary powered siren and the hazard warning lamps will be activated for a period of 30 seconds. Any additional disturbances that occur during trigger duration will not extend its duration.
At the end of the trigger duration the DWA will return to the Perimeter armed state. If the DWA was originally Volumetric armed then provided the tailgate and the two doors are closed it will return to that state. There will be a delay of sensor settle time before the volumetric or the tilt sensors are valid trigger sources. Only new disturbances will trigger the alarm, such as a closed door that subsequently opens. If a door is left open it will not retrigger the alarm unless it is closed and then re-opened.
Also there is a limit to the number of triggers that are allowed in one setting period. This is a limit on the total number of triggers regardless of the source. If the total number of triggers meets this limit there will be no more triggers in that setting period.