Why would a scan on my truck 1998.5 dodge 3500 24 valve pull up Mercedes indo

My simple scanner does that too. When there is a companion module fault the scanner needs to be told what to expect so I have to manually select chrysler then it works ok.

 

I suspect it's because the ISO9141 Protocol which is k-line and L-Line bidirectional comm. The protocol supports multiple ECUs/PCMs on a shared comm bus. The k-line was popular on many European cars at that time.

 

OBDII and computers on cars were not well standardized at that time and many manufacturers winged it.  So there is a lot of unsupported features.

Thank you!  I'm learning but I'm not there yet!