Hi,

I've got a 2002 TD6 which has recently been acting up. It started with message "air suspension inactive" flashing up intermittently, then the SRS light came on in the dash, have to turn the key twice to unlock steering lock, key fob for unlock/lock doesnt work. Upon plugging in IID diagnose i initially got K bus fault in the EAS module, and later on a few different faults on the SRS module, like driver seat buckle, airbag firing circuit etc.

If i reset all the error codes they will come back after a short while, starting with EAS K bus fault and then the SRS codes abit later on.

I have unplugged the headlight leveling module, with no change in behaviour.

Any help or ideas on where to troubleshoot would be much appreciated.

BR
John

If you have access to an oscilloscope then you can look at the K Bus (which unlike CAN, is a single ended bus) and see the quality of the signal i.e. whether the edges of the square wave are clean and crisp transitions from high to low, and back again.
If they are not, then you can individually disconnect one control unit at a time until you find which one is causing the disruption.

Another technique is to use a resler interface www.reslers.de/IBUS/index.html to connect a PC running Navcoder software www.navcoder.com , so that you can see the various messages being sent around the bus. You should be able to see which messages are corrupt, and again by disconnecting control modules you should see when the data starts to appear sensible.