PCM(-) Low Reference the Same at Sensor Connector?

I've uploaded a pic of my Vantage Pro screen. Trying to help someone with a 2003 Trailblazer ECT circuit. But the question concerns the Vantage Pro screen instructions. After the initial test with the connector disconnect, the second part of the test states to plug connector back in, then apply the yellow (Vantage) lead to "PCM (-)" and black (Vantage) lead to known good ground. Using the image, are "PCM (-)" and connector "Low Reference "blk"" one in the same? I know (I think I know) that "Low Reference" is sensor ground typically, but is that what I should use as the "PCM (-)" for this test? Thanks.

rockp2 wrote: Using the image, are "PCM (-)" and connector "Low Reference "blk"" one in the same?

I think that's what they meant to say, but they ended up using the term 'PCM (-)' instead of Low Reference. :blink: Some confusing terminology especially because GM, for whatever reason, has to call their sensor grounds 'Low Reference'. *rolls eyes*

You've got the right idea on this one! OR, if you have access to scan data, you can short the two ECT wires together and watch for the ECT voltage PID to go to zero.

we aftermarket techs have to know all these manufacturer names for grounds. I always get fords confused when they call there sensor grounds signal return. I always think that's the signal the sensor produces and sends to the module.

Thanks very much for the replies Tyler and Cheryl. I just couldn't figure out why the Vantage Pro wouldn't state "Yellow to Low Reference" instead of "PCM(-)". With my newness to scope world, wondered if "PCM(-)" might be something completely different and I was missing it. But your replies cleared it up for me completely. Thanks again!

No problem! It's tough enough when OE's have their own electrical language, then Snappy has to throw theirs in the mix. :lol: