EWS III (3.3)
EWS III(3.3)
EWS III(3.3) is installed in the 1998 E38 from 5/97 production, in the 1998 E39 from 9/97 production, in the E46 beginning Of production, in the E52 and E53 beginning of production.
Purpose of the System
The purpose of the EWS III(3.3) system is to add greater theft protection by providing a higher level of sophistication than previous systems. The new "Rolling Code" provides an additional theft deterrent through a changing Of the SN everytime the vehicle enters the start sequence.
Components changed in the EWS III(3.3) system include:
- EWS III(3.3) Control Module.
- DME Control Module.
- Transmission Range Selection Input.
Workshop Hint:
While it is possible to initialize a key to another vehicle to check for remote operation, use caution. All keys for Both vehicles must be available. The initializing process, causes loss of operation of keys previously initialized.
All keys must be initialized at the same time.
System Components
EWS III(3.3) Control Module
The EWS III(3.3) Control Module uses the same 13 pin connector as EWS III(3.2) but functions differently. The EWS III(3.3) module has a "Rolling Code" ISN assigned to it during manufacture. The "Rolling Code" is burned into the module and cannot be overwritten by ZCS Coding or DME alignment procedures.
The "Rolling Code" is a one way signal from the EWS III(3.3) control module to the DME and is similar in operation to the data exchange between the EWS control module and the key transponder
The "Rolling Code" will be different each time the start operation is begun. The "Codes" are taken from the "Rolling Code Table" which is assigned at the factory to the EWS III(3.3) control module and the DME.
DME Control Module
The DME Control Module has changed in that it is not the source of the ISN but now only stores the "Rolling Code". It compares the "Codes" to those sent to it by the EWS III(3.3) control module. The "Rolling Code Table" assigned to the DME must match the table in the EWS III(3.3) module. The "Rolling Code Table is "burned" into the DME during the programming of the DME and cannot be change once "burned".
Transmission Range Selection Input
With the introduction of the SKE type connectors on Transmission Control Modules the direct input from the Transmission Range Selector Switch is eliminated. The input for range selection is now received from the AGS Control Module.
On manual transmission vehicles clutch status is input directly into the DME.
Principle of Operation
The starting sequence of the EWS III(3.3) is as follows:
(Same as EWS III(3.2)
- The key is inserted into the lock cylinder and switched "ON". The EWS III(3.3) control module is powered through KLR and sends a 125kHz AM signal to the ring antenna. The AM signal induces voltage in the key coil and powers up the transponder.
- Powered up, the key transponder sends the key identification code to the EWS III(3.3) module. The EWS III(3.3) module verifies the key identification code and checks to see if the key is enabled. If the key is correct and enabled, a password is sent to the transponder over the 125kHz AM signal through the ring antenna.
- When the transponders accepts the password, it releases the changing code which it received from the EWS III(3.3) module during the last start-up operation to the EWS III (3.3) module via the ring antenna.
- The EWS III(3.3) module compares the changing code received from the transponder with the code stored in its memory and it they match the process is allowed to continue. The EWS III(3.3) module looks at the other inputs for correct status (e.g. Code function not active, Transmission in P or N or clutch depressed, engine speed below specified RPM) and energizes the the internal relay to begin starter operation.
New to EWS III(3.3)
- While energizing the internal starter relay, the EWS III(3.3) module calculates a stored code from the "Rolling Code Table" and sends the calculated results to the DME.
- On receipt of the "Rolling Code" from the EWS III(3.3) the DME calculates it's own stored code and compares its results with the code it received from the EWS III(3.3).
If the "Codes" match the drive away protection is released and injection and ignition are enabled and the engine starts.
If the "Codes" do NOT match, the DME "rolls forward" to the next code according to the "Rolling Code Table" and makes the same calculations. The DME continues this "forward roll" up to a maximum of 200 times or until a match is found. Failure to find a match will result in the engine cranking but not starting.
- When the ignition is switched off and no engine RPM is present in both the DME and the EWS III(3.3) control module each module will automatically "roll forward" to the next predetermined code based on the "Rolling Code Table". This new code is used for the next starting sequence.
Workshop Hint:
If during diagnosis the key is switched on while the DME or EWS modules are "Disconnected", the alignment procedure will need to be carried out.
The "Alignment" procedure may be carried out an unlimited number of times.
Replacement Procedures
Keys
Up to 6 additional keys may be ordered as replacement keys. The EWS II control module is codeable for only 10 keys (4 delivered with vehicle and 6 replacement).
EWS III(3.3) Control Module
Replacement EWS III (3.3) Control Modules are ordered VIN specific. The module is received with the same "Rolling Code Table" as the original module. Once ZCS coded, the DISplus software "resets" the current rolling code in the DME back to "Rolling Code" #1, providing synchronization of both modules.
DME Control Modules
Replacement DME Control Modules are "oft the shelf" and must be programmed for the specific vehicle. After programming the DISplus software informs the EWS III(3.3) control module that a new DME has been installed. The next time the ignition is switched on, the EWS III(3.3) module will send the entire "Rolling Code Table" to the DME and reset it to "Rolling Code" #1.
The DME will automatically bum the "Rolling Code Table" into its memory. Once the table has been burned into the DME memory it can NOT be changed. For this reason once a DME is "Married" to the vehicle it will not work in any other vehicle.
Under certain condition "Alignment" of the DME and EWS III(3.3) modules may still be necessary. The alignment procedure only resets the code table to code #1 it does not change the "Rolling Code Table".
Key Activation
Keys that are lost or stolen may be deactivated or made to not operate the starter functions. The SERVICE FUNCTIONS of the DISplus or MoDic for EWS III(3.3) contains a "bar/release code" function that activates and deactivates keys of the EWS III(3.3). Any key may be "Barred" except the key in the ignition at the time of deactivation. The lost or stolen key can be identified by the identification of the remaining keys.
There is no limit to the number of times a key can be activated/deactivated.
Workshop Hint:
While checking key operation, don't forget to wait 10 seconds before inserting the next key.
You can not BAR the key in the ignition.
A dead key battery does not affect vehicle starting.
Keys without replaceable batteries are not charged if the ignition is in the KLO (Off) position.