The DB9 has two PCM's that control each side of the engine. When plugging in an OBD reader to read error codes, the manual refers to making sure you are looking at the right (correct) side of the engine,

There is only one OBD port on the car, how does one know which side of the engine the reader is displaying, and how would you read the other side?


Thanks

 

Both sides read thru the single OBD port. The other port is the chassis port and can only be read with the AM dealer software.

 

I see the reader shows both sets of data at the same time