Driveaway Protection System Interfaces
EWS 1(1-94 thru 12-94 production)
The EWS I system was added to all vehicles in January 1994. It is controlled by the Central Locking System of ZKE, by the On-Board Computer code function (if equipped) or by the DWA system (E31).
The Starter Immobilization Relay is activated when;
- the vehicle is locked from the outside (Central Locking - GM output to Relay).
- the On-Board Code function is set.
- DWA is activated (E31).
An activated relay performs two functions to deter vehicle theft;
- Ignition and Injection functions of DME are disabled (switched high output signal.)
- the KL 50 start signal circuit is opened to prevent starter operation.
DRIVEAWAY PROTECTION SYSTEMS INTERFACE
EWS II (from 1-95 production)
EWS III(3.2 - from 9-96 production with M5.2 Systems)
The EWS II and DME control modules are synchronized through an individual serial number (ISN). The ISN is a unique code number that is permanently assigned to the DME and also stored in the EWS II control module. The ISN must match every time the ignition is switched "ON", before the DME drive away protection feature will be cancelled.
- Engine control modules designed to operate with the EWS II system will not interchange with engine control modules from previous models.
- The ISN replaces the BC Code input to the DME control module.
- The ISN is unique to each DME and cannot be changed or overwritten. The ISN is transferred and stored in the EWS II Control Module using the DIS or MoDiC.
- Everytime the ignition is switched "ON", the ISN number is sent from the EWS control Module to the DME, as a digital coded signal. The numbers must match before the DME will release the driveaway protection.
- The ISN is continuously sent to the DME as long as the ignition is switched on. The DME will ignore the loss of the ISN after the engine is running.
DRIVEAWAY PROTECTION SYSTEMS INTERFACE
EWS 3.3 (from 5-97 production with DME 5.2.1 control systems)
EWS 3.3 is installed in vehicles equipped with M5.2.1. The system inputs remain unchanged compared with the 3.2 system, however; the ISN output has changed. The ISN signal is now a "Rolling Code ISN".
- Rolling code tables are rigidly assigned. For this reason, DME control modules can not be swapped from another vehicle and re-aligned for troubleshooting purposes.
- Replacement EWS 3.3 control modules are ordered VIN specifically They are received with the same rolling code table as the original module. Once ZCS encoded, the DIS software "resets" the current rolling code in the DME back to rolling code #1, providing synchronization in both modules.
- Replacement DME control modules are "off the shelf parts" and are "blank". After DME programming, the DIS software informs the EWS control module that a new DME has been installed. With this information the EWS will send the entire rolling code table to the DME on the next key on condition. The DIS software then informs the DME that the first code it receives from the EWS is actually the rolling code table. When it's received DME automatically "burns" it into it's memory. When reprogramming is completed the systems (DME/EWS 3.3) must have the alignment procedure performed.
- The alignment procedure in the SERVICE FUNCTIONS menus of EWS or DME "resets" the rolling codes back to #1 in each module. It does not change the coding tables. The ignition key must be switched off for 10 seconds after the adjustment is completed.