Is the single wire class-2 line required for flashing high speed GMLAN ECUs?

Hello all,

I am making a stand alone harness to do some bench testing / flashing of an E40 PCM. This particular module is from a 2006 GMC Envoy XL (E40 PCM on an LH6 motor.) All I want to do is connect to, and flash, the engine controller in a complete stand-alone environment. No transmission controller or body control module will be used.

The wiring diagrams I have for this vehicle are a little vague and even though the class-2 line is connected to the DLC / ALDL / OBD-OII port, I'm skeptical that I actually need it. Was wondering if anybody else has had experience with this.

Thanks.

Attachment 84768

http://www.gmtruckcentral.com/articl...h-harness.html

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Originally Posted by DGS

http://www.gmtruckcentral.com/articl...h-harness.html

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That's uh... not the correct engine controller. The P59(?) referenced in your link doesn't use high speed GMLAN like the E40 does. Thanks for the link though.

Also to follow-up for anyone who lands here after searching for the same question I originally had,

...the class-2 single wire serial data connection is NOT used for flashing, tuning or logging on an E40 engine control module. Everything is done through the 500k high speed GMLAN (CAN) bus. It is not required when making a stand alone bus.

This has recently been verified on my bench tests.

Yes, you are correct. If you look at the pdf file link in the document, it lists many controllers and what terminals are needed.