L8: Check For Short CAN+ to Ground

At the J1962 connector measure the resistance between pin 6 & ground Repeat for J1962 connector pin 14 & ground

Is the resistance > 2.5 & < 4.0K ohms?

Yes
Good
Go to L9

No
Bad
< 2.5K ohms, check for a short to ground

No
Bad
> 4.0K ohms, check for a open circuit