06 CTS, No Crank, No Communication with ECM, U1000

Unhook tcm put a jumper wire in the cam wires and check from dlc should have close to 0 ohms. If you do check the cam wires coming out of tcm to ecm for an open

Use a turn signal bulb like a 3157/ 3057

I can't find a connector end view of the TCM connector. I can see the can bus wires. I was able to get continuity on the can h. I'm not sure about low. It tried a few different pin holes with no success.

Also the can h and l do not pass through the TCM to get to the ECM. There are no pins in the TCM. I would have to pass through the connector.

Unplug tcm look for pins 20 and 21 tan and tan/BLk wires. Put jumper wire in between the 2 terminals recheck for continuity at pins 6 and 14 at dlc. Should have continuity. Let us know what you get

Here is what i got. Please confirm because i see CAN lines slightly different. Then diagnosis logic is a little different.

I still see it as going from dlc going In tcm then out of tcm to ecm because it’s not a 6.0 liter. Also has class 2 coming in ecm

Yes Cheryl, you are right. My mistake

Ok guys, I rechecked my logic.

*ECM is not communicating through class 2 (even with continuity between modules (checked by P320)), neither through CAN with TCM.
*voltage in class 2 network could be generated by the other modules, so we still don´t know if ECM is sending something.
*If you have a CAN lines issue, that shouldn´t be affecting class 2 and viceversa.

The only issue i can imaging is an ECM ground issue which is altering voltage level in chip inside ECM in charge of communication.