There are two types of Benz keys: chipped key and infrared key. Old Benz cars use flip key fobs, 7935 chip inside them. Newer Mercedes Benz start to use infrared key around 1999, the key transmit infrared SSID rays to electronic ignition switch (EIS), if the SSID from key is same as EIS, the lock will be unlocked.
It looks Mercedes-Benz no longer makes replacement chipped keys for old models, if a pre-2000 Benz need to have key programmed, a local locksmith would be a better option.
In this post we will show you how to program an infrared key or chipped key for Benz.
Method on programming infrared key
When programming keys, we need to read the data of EIS, calculate key data and write it into key fob. The CPU of EIS has two types: Motorola and NEC. Infrared keys has three types: Motorola key, NEC key and BGA key. Check following steps:
Step 1: read EIS dump
Some key programmers can read EIS data via OBD port without disassembling, and some can’t. If the key programmer can’t read by OBD way, we have to disassemble EIS from car, open it and find CPU, read CPU with key programmer like Yanhua key master, VVDI Prog…Save the dump in bin.
Step 2: calculate key dump
Benz key calculator is required in this step. Generally we use Mercedes Benz SKC key calculator, easy and quick operation. 1. Start software, load EIS dump in step 1, then we can see the SSID, VIN, password, odometer… ensure all of the values is displaying, if not, it means some data is lost, can’t calculate key dump that start the car. 2. Select unused key position (key status is in right bottom). 3. Click “CALC KEYS”, wait around 10 minutes, calculation finished and generate key dump which located in file folder where EIS dump stored. One dump is for one key.
Step 3: Write key dump into key fob
There are many key programmers can write key dump into key fob, follow the instruction of the devices, you will succeed.
Method on programming chipped key
We take 2015 Benz ML350 for example which equipped with chipped key fob, immobilizer data is stored in chipped key, AAM or EAM and DEM. Programming this key need to do read immo dump and write key, check below details:
Step 1: read immo dump
Disassemble AAM which located in under steering wheel, open the AAM, two electronic board will be found, and both of them has CPU chip, the Motorola CPU No. MC68HC705X32 we need is on smaller electronic board, find it and read with key programmer like Yanhua key master, VVDI Prog…, save the dump.
Step 2: write key
After reading CPU dump, need to write key with key programmer like Tango, VVDI2 and TM100… prepare 7935 chip and follow the instruction of the programmer you will use to finish writing key.
Step 3: Active key fob
We need to use Benz remote module as below photo, connect AAM and remote module with cable, and install the chip programmed in step 2 into key fob which from the module, and then key fob is active.
At present, there are some key programmer like FVDI can read AAM via OBD without disassembling AAM and program keys.
DISCLAIMER: The technology and software in the blog are only used for technical research and auto repair, and are not allowed to be used for illegal purposes, We will not be responsable for any direct and indirect damages from the use of the file created by this page.