2010 Chevy Traverse Intermittent No Start

#mechanic #diagnostictroublecode #broken
Transcript:
Todays video is an in-brief diagnostic process on a 2010 Chevy Traverse that will not start intermittently. In fact the vehicle was driven to the shop and parked out front for a short time, and then failed to start.
After the vehicle was pushed into the shop a basic health check is performed including checking general maintenace, upkeep, fluid level and condtions, etc.. which I have not shown in this video.
I attempted to start the vehicle and lets define this particular no start as a no crank, no start.... in other words the starter is not even attempting to turn over the engine. Some people might perceive this as a dead battery, but a quick visual indicator to me that the battery is ok were the headlights and interior lights are all at full brightness, so this has to be something else.
I also noticed there was no gear indicator so the no crank situationm makes sense, the starter will not be allowed to operate if the vehicle cannot sense that it is in park or neutral.
Next I connected the scan tool and did a vehicle wide code scan.....during this point of the diag we are gathering information and not doing any intrusive testing. What stuck out to me immediately as the source of our no start is that the Engine control module and the Transmission control module are not communicating with the scan tool.
There were several codes stored in multiple modules, but the only thing that matters to me is that most of them are communicating, and most of the codes point towards a loss of communication with these two mission critical modules..
The next step from here is to consult the wiring diagrams for both the ECM and TCM, I noticed they both receive an ignition power feed from the ignition main relay and the both receive a common ground at G110.
I skimmed the high speed GMLAN diagram, but I felt the problem lies elsewhere due to the fact most of the modules are still communicating.
During that health check earlier I immediately noticed the engine has had some recent major work done so im thinking I need to go check out that G110 ground.... I found G110 is in a hard to access spot, but its attached and its good and tight... so I thought ok another quick check is going to be to check for power being fed to the associated fuses by the Ignition Main Relay, but before I do that im going to make sure this isn't a power moding problem, the BCM or Body Control Module is the power mode master for all the others modules on the vehicle so I need to make sure the BCM sees the ignition key data properly and after a quick check with the scan tool everything looks ok there...
Moving on to the fuse panel where the Ignition Main Relay is located I noticed a problem right away...with the key in the ON position there is a buzzing sound coming from the fuse panel, sounds like a relay fluttering on and off.
I checked for power at the fuses downstream of the Ignition Main Relay with a test light which confirmed my suspsicion that is where the noise is coming from.
I checked and load tested the power feeds in to the Ignition Main Relay which turned out to be ok and then I load tested and confirmed this is definetly a ground problem on the control side of the relay...as you can see the test light will light dimly, but the headlamp bulb won't light at all due to the circuit not being able to carry the load. I'd also like to note I am only touching the test probes to the fuse panel terminals lightly, you don't ever want to jam anything, but the proper test lead into an electrical terminal.....moving on.
At this point I've gathered enough information to determine I need to do some intrusive testing which may involve a lot of time gaining access to modules and connectors.
Unfortunely the ground circuit information for the relay was missing from the power distribution diagram and I had to check another information source, or I could have saved some time because once I found that missing piece of information I was surprised to find an old friend... Looks like our old friend G110 needs a much closer look. And then I did find the missing information on the ground distribtion diagram for G110.
G110 happens to be in a really tight spot and hard to access, I had trouble removing, inspecting, and cleaning the metal surfaces... but after the effort the test light now lights brightly, communication is restored, and the engine now starts and runs.... Thanks for watching
- Dad

[@user-vk9hw2zr2p]

where on the car is the G110 that you had to fix and where does the other side connect? thank you

[@DadsGarageDiagnosticSpecialist]

G110 is located on the top, on the cylinder head near the front of the engine. In-vehicle location would be passenger side under the windshield area. G110 is the ground for multiple devices so there are multiple ends. Thank you for commenting.

[@robertwisdom1273]

Why will my traverse activate starter in the acc key position

[@DadsGarageDiagnosticSpecialist]

Usually that will be due to shorted wiring or aftermarket wiring hacked in. Thanks.