Anti-Theft (DWA) System
Anti-Theft (DWA) System
(Retailer Installed Accessory Option)
All E46 vehicles are factory prepared (prewired and GM programmed) to provide the DWA function. The DWA system components are available as a retailer installed optional accessory. Once the DWA system components are installed the GM must be encode to recognize the installed components and carry out DWA functions. This is done with the ZCS "Retrofit" program function using the DIS or MoDiC.
The GM utilizes existing components and/or circuits as part of the DWA system:
- Door lock hall effect sensor contacts (door open/closed).
- Trunk lid switch contact (monitored for closed trunk).
- Trunk lock key position switch (located on the trunk lock, this switch signal prevents DWA from activating if armed when the trunk is opened with the key).
- Hood switch (monitored for closed hood, located under the hood).
- DWA status LED (part of rear view mirror).
The DWA optional accessory kit includes the following:
- Tilt sensor (pre wiring in area of installation in right trunk area).
- UIS Interior compartment monitoring sensor (pre wiring in area of installation in center headliner).
- DWA siren (pre wiring in area of installation right cowl area next to IHKA housing).
Components
Door Contacts
As mentioned in the Central Locking Section, the door lock contact hall effect sensors provide status of door open/closed.
- When the door latch is closed, current flow through the sensor is < 5 mA (0).
- When the door is open, current flow through the sensor is > 12 mA (1).
The GM will activate the siren if a door open signal becomes active when the DWA is armed.
Trunk Lid Switch Contacts
The trunk switch contact is located in the trunk lock actuator assembly. When closed, the trunk contact provides a ground signal to the GM signifying a "closed trunk". The GM will activate the siren if the trunk switch contact ground signal opens when the DWA is armed.
Trunk Lock Key Position Switch
Mounted on the trunk lock cylinder are two switches:
- Valet position switch: With the key lock in the valet position, this switch provides a ground signal to the GM. The GM locks out the interior trunk release button preventing the trunk from being opened.
- Trunk opened with key switch: When the trunk is opened mechanically with the key, this switch provides a ground signal to the GM preventing the DWA from activating if armed.
Hood Contact Switch
Located on the right side engine compartment, the hood contact switch provides a ground signal to the GM signifying an open hood.
The plunger of this switch can be pulled up past a detent causing the switch contact to open. This feature can be used to simulate a closed hood with the hood open when diagnosing the DWA system.
DWA LED
As on previous systems, the DWA indicator is located in the rear view mirror. The LED is equipped in all E46 vehicles and is not part of the retailer installed accessory DWA system.
The LED is provided with constant battery voltage (KL 30). The GM provides a switched ground signal providing the various blinking signals used to convey DWA status to the vehicle operator (covered further on).
Tilt Sensor
Located in the right trunk area above the battery, the tilt sensor is an electronic sensing device with the sole purpose of monitoring the vehicle's parked angle when DWA is armed.
This sensor is a new, one third smaller, solid state version of the liquid filled version used on previous systems.
The sensor requires three signal wires to perform its function:
- KL 30 - Constant battery voltage
- Signal "STDWA"; switched ground input signal provided by the GM indicating DWA armed/disarmed status. The tilt sensor is used as a splice location for the STDWA signal to the Siren and FIS interior protection sensor.
- Signal "NG"; switched ground output signal provided to the GM. The signal is used for two purposes,
1. As a momentary acknowledgment that the tilt sensor received STDWA and is currently monitoring the vehicle angle.
2. If the tilt sensor detects a change in the vehicle's angle when DWA is armed, signal NG is switched to inform the GM to activate the siren.
When the tilt sensor receives the STDWA signal from the GM it memorizes the vehicle's parked angle. The angle of the vehicle is monitored by the solid state electronics. Once armed, if the angle changes, the tilt sensor provides a switched ground signal to the GM to activate DWA.
Interior Protection (UIS)
The E46 introduces a new interior protection sensor known as UIS. Similar to the FIS previously equipped on the E38/E39, the UIS monitors the vehicle interior for motion through ultrasonic sound waves. The UIS is a combined transmitter and receiver.
The interior sensor is mounted in the center of the headliner panel even with the "B" pillar. Due to the design of the vehicles interior, the sensor is uni-directional and must be installed in the proper direction to ensure proper operation of the system (trim cover ensures directional installation).
Every time the DWA system is armed (signal STDWA), the sensor adapts to what ever objects might be stationary in the interior .
The sensor emits ultra sonic waves in a programmed timed cycle. It receives echoes of the emitted waves.
The UIS amplifies the received sound wave signals and compares them with the transmitted waves. The UIS also checks the incoming echoes for background hiss (wind noise through a partially open window) and adapts for this.
- If the echoes are consistently similar, no movement is detected,
- If the echoes are altered, (inconsistent), the UIS determines motion in the interior compartment.
If motion is detected, the UIS changes to a constant cycle and the echo is compared again. If the inconsistency is still present the UIS sends the activate siren signal (IN RS) to the GM.
As with the tilt sensor, the FIS is also switched OFF when the vehicle is locked two times within ten seconds. This allows the sensor to be switched OFF for transportation purposes.
Alarm Siren
The siren from the DWA accessory kit is installed in the vehicle cowl on the passenger side of the vehicle. This location provides a secure position with loud acoustic output.
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.
The rechargeable battery will allow the siren to sound if it or the vehicle's battery is dis-connected. The siren battery is recharged, from the vehicle's battery when DWA is not in the armed state.
The siren has four wires connecting it to the system; KL 30, KL 31, Signal STDWA (arm/disarm signal from GM), and Signal NG (activate siren output signal to the GM)
The arm/disarm output signal from the GM (STDWA) is provided to the Tilt sensor, FIS sensor and the siren simultaneously. The arm/disarm signal is a switched ground that signals the components of DWA armed/disarmed status.
The activate siren signal (NG) is high whether DWA is armed or disarmed. If a monitored input activates the alarm, the high signal to the siren is switched to a 50% duty cycle at the GM. The control circuitry in the siren activates the siren driver. If the DWA is armed and the battery is disconnected the siren recognizes the normally high "NG" signal as suddenly going low, the siren is also activated.
DWA Arming/Disarming
- The DWA is armed every time the vehicle is locked from the outside with the door lock cylinder or FZV key.
- The LED in the rear view mirror flashes as an acknowledgment along with the exterior lights and a momentary chirp from the siren.
- The GM monitors all required input signals for closed status (door closed, trunk closed, etc.) The inputs must be in a closed status for a minimum of 3 seconds for the GM to include them as an activation component. If after 3 seconds any input signal not in the closed status is excluded (this is acknowledged by the DWA LED) preventing false alarm activation's.
- If the DWA is armed a second time within 10 seconds, the tilt sensor and interior protection sensor are also excluded as alarm activation components. This function is useful if the vehicle is transported on a train or flat bed truck to prevent false alarm activation's.
- While armed the trunk can be opened with out the alarm being triggered as follows:
- If opened with the trunk remote button via the FZV the GM prevents the alarm from activating. (This feature is customizable under the Car Memory function).
- If opened with the key at the trunk lock cylinder the trunk key position switch signals the GM and in the same manner prevents the alarm from activating.
In either case, when the trunk is returned to the closed position, it is no longer considered as an activation signal.
Panic Mode Operation: When the trunk button is pressed and held, the GM is signaled to activate the siren for the Panic Mode. The panic mode is function with either an armed or disarmed DWA system.
Emergency Disarming
Emergency disarming occurs automatically if a key is used to turn the ignition switch on and the EWS III accepts it. The EWS III signals the GM to unlock the doors and deactivate the DWA.
Alarm Indication
When the alarm is triggered, the siren will sound for 30 seconds. At the same time the low beam headlights and four way flashers will flash for 5 minutes. The GM signals the the LSZ via the K bus to flash the lights.
Following an alarm trigger, the system will reset and trigger again if further tampering is done to the vehicle.
DWA LED Status
DWA STATUS DWA LED CONDITION
Disarmed OFF
Armed Continual slow flash
Armed with one or more monitored Rapid flash for 10 seconds, then continual slow flash. inputs not in closed position
(ie: trunk not fully closed, etc)
Alarm activated Rapid flash for 5 minutes, then continual slow flash.
Rearmed in less then 10 seconds. ON for 1 second
Disarmed after activated alarm Rapid flash for 10 seconds, then OFF