Hello,

I recently purchased a 2000 GS, the owner said the ECU was possibly bad. I am not receiving any OBD codes, nor will it connect. The car will turn over, but no start up. I tried a second ECU, with the same model, and it wont connect with OBD either. Could be both ECUs are bad? Maybe someone can help. Thanks!

Edit: OBD fuse in driver kickpanel fusebox is not blown.

 

Sounds like there are some wiring issues.
Have you checked the EFI fuse in front of the battery?
Wilbro666 has a full wiring diagram for the GTE that you can use as consideration if it's a GS300. Lextreme may have the GS4 diagrams. Good luck

 

Yer like TW99GS300 said, its probably a wiring issue / blown fuse.
Sounds like the ECU isn't being powered up because the engine wont start and theres no connection to obd. Ecu cant connect to obd if its not powered up.
After checking all relevant fuses, you need to check all 12V and 0V wires going to the ecu.