TM100 Program Honda CB400 08 motorcycle key

Here is the instruction on programming key for Honda CB400 2008 motorcycle with TM100 key programmer.


Honda CB400 motorcycle 2008 year has the same EFI engine and immobilizer system as Honda car. We can only write to add key when all keys lost. Follow steps below:


1 Dissemble ECU

ECU immo box locations are based on different models. But usually can be found below the seat cushion. CB400 engine computer is located under the tank, we see the model: 38770-MFM-702, as shown below.


2. Read ECU data

Waterproof is very important to motorcycle, so we have to deal with the pouring sealant first.

Tear off the sealing glue with hand tools in the position picture below shows. Be careful not to damage the circuit board. 

Found the IC circuit chip 93C66.


Dismount soldering iron 93C66, read 93C66 data with Xprog M ecu programmer.

Save data.


3. Read & write key

We can write CB400 keys with TM100, VVDI, Tango etc key programmers. Our engineer used TM100.

Connect TM100 with computer, enter main menu, select KeyMaker

Select brand:Honda-> Motorcycle->93C66 chip model

Then upload 93C66 data just read by xprog


TM100 software will display the key numbers. Select key position to be programmed.

Insert brand new 7936 chip (normal  46 chip is OK) into the TM100 coil

Click on Generate key


TM100 will write 7936 chip data to original file and generate new 93C66 data file automatically.

Re-write the new generated 93C66 data to 93C66 chip on IC circuit by using Xprog m.

Resolder the engine computer back to motorcycle.

Turn ignition ON

Immo indicator OFF

The new key is working.


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