the megohms readings to ground really dont mean anything. you need to measure from the relay socket to ecm pin on that yellow wire to see if its low(should be), then measure for voltage on the pins i mentioned and ohms to ground on the orange/black wires i mentioned

I am measuring no voltage drop along the yellow wire, it checks out at both 11.89V at the relay socket, and also coming off of the ECM Pin. The red wire on the relay socket is ready 12.05V. The Black wire is grounded with no resistance.

The Orange and Black wires are reading as follows.

25 M Ohm between Pin 1 and 12, when battery is hooked up and key is off.
720 M ohm between pin 1 and pin 12 on the ECM, with battery hooked up and KEY ACC/ON position, this will hold after key is turned off, and doesn't change when trying to start.

Not sure if this matters, but resistance on these wires between Ground are:
PIN 17 Key Off: 0 M OHm
""""Key ACC: 15 M ohm
"""Key ON: 48 M Ohm
""Key Start: jumps up to 320 M ohm

PIN 1 Key Off: 9 M ohm
Key ACC: 20 M ohm
Key ON: 141 M Ohm
Key Start up to Infinity?

if you really have 12v on the yellow wire the relay should close and crank the starter. did you try jumping the red to the purple at the relay?

Just found this Post from AC Delco tech tips. It is from September 2013.

techtips


Body Control Module Grounds - August 2013
2006-2011 Buick Lucerne, Cadillac DTS, 2008-2014 Buick Enclave, Cadillac CTS, Chevrolet Express, Chevrolet Traverse, GMC Savana, 2007-2009 Cadillac SRX, Chevrolet Equinox, Pontiac Torrent, 2007-2014 Cadillac Escalade models, Chevrolet Suburban, Chevrolet Tahoe, GMC Acadia, GMC Yukon models, 2006-2008 Chevrolet Monte Carlo, 2006-2013 Chevrolet Impala, 2007-2013 Chevrolet Avalanche, Chevrolet Silverado, GMC Sierra, 2007-2010 Saturn Outlook, 2008-2010 Saturn VUE, HUMMER H2

The Body Control Module (BCM) may be damaged when the module is supplied with battery power and the ground path is removed. Remove the negative battery cable first before removing a BCM ground.

BCM Ground Path
The BCM ground path passes through the following components. The negative battery cable must be removed on these vehicles when removing the components.
Instrument panel electrical center, 2008-2010 HUMMER H2
I/P splice pack, 2008-2010 Saturn VUE
Other Affected Components
When removing a ring terminal ground, splice pack connector, or inline harness connector on all the models listed, remove the negative battery cable if it is determined that it is a BCM ground path.

For example: If the BCM grounds become disconnected, internal damage to the BCM will occur. Other systems controlled by the BCM will also be affected, such as an inoperative or intermittent condition in one or more of the following systems:
Interior lighting will remain on or will not work
Exterior lighting will remain on or will not work
Remote keyless entry
Door locks
Power windows and mirrors
Remote vehicle start
Remote trunk release

I am gone for a few days for work, but will be back home later this week to check out Ground wires on the BCM under the dash. this would explain why more door locks are clicking to unlock when key is in START position.

I will also try the jumper wire from red to purple on the Crank relay sockets and see if the start will turn.

After finding the above post I am thinking my BCM was likely shorted internally and damaged, not my ECM as originally thought.

either condition would not give you 12v on the yellow wire, unless its some transient voltage for circuit detection which is what i was saying when i said "really there". it may be beneficial to test it with a light, because if you put a real load on it it may go away. if it does then you know its something like the bcm or pcm

So the relay is defineitly not closing, as i can jump from the red wire to the purple wire and the starter will crank.

I have bought a new BCM and will have that flashed within the next few days. After reading the techtip thread, and knowing that when I do crank the ign. to START the doors keep unlocking, so I am 95% certain my BCM is bad, and the culprit for my no-start situation.

Will update when new BCM is installed and flashed.

So the problem was with the keys not being read as learned. Security light wasn't flashing so it was half learned half unlearned. Wierdn but needed mechanic with tech 2 scanner to force ECM into learn mode and accept the keys as learned. Bottom line, cost to scan and relearn was $130, wasted about $275 on computers not needed.

Hi finally had to tow my 2008 torrent6 miles to a GM dealer whoo foung the ECM was burned out. No reason just that was it. Hope my troubles are over but have doubts. chuck Ps thanks for the help.