2009 Chevy Traverse LTZ stuck in park

My 2009 Traverse has sat mostly unused for almost all of COVID. I just recently got in it to try to start it and my recent problems began with a failed starter switch (in the steering column). I got a replacement on amazon and installed it and it worked. That was about 4 months ago and its sat since. I went back out to it a month ago and the battery was dead. I got the (AGM) battery in 2017 and when I put it on my charger it read 3 volts. I removed it, charged it and it seemed ok, but then died again 3 days later when I went back out to start it. My charger then said “SUL” (sulfonated) and I went to get a new battery (AutoZone confirmed bad batt). I put in the new one and tried to start it and am getting a “hood open” sensor warming and the car will not start. I researched it and jumpered pins B and C in the sensor cable/block to ground the hood open wire (B) to ground (C) to test the sensor. Still will not start. Taking a closer look, I now see there are other issues with…the electronics? I’m seeing other issues, I’m getting a Traction Control CEL and my lift gate will not open (checked/cycled switch on console). With the key in the On position I’ve checked a few things (but probably not all). With the key in the On pos., I’ve noticed the A/C doesn’t work (appears to be dead), turn signals do not work, but other things do work (interior lights), door open sensor, radio is fine, clock is fine, headlights appear to work. I’ve visually inspected the fused under the hood and none appear to be blown. I even pulled the 30A fuse for the liftgate and jumpered the contacts and tried to open–no go (but it does “click” at the fuse block area). My fuel indicator indicates empty and sometimes the needle cycles end-to-end (like the other gauges) when first inserting/turning the key. When it does cycle, it still indicates empty. I have not manually checked my fuel level but when I last drove it, I filled it as I knew I was going to be using it very little. When I plug in my OBDII reader, I get “error” after a period of normal-looking-trying-to-read-the-computer. I’ve used this reader many times on this vehicle in the past to reset TPS and other intermittent codes e.g., occasionally throws a catalytic converter code every other month or so, etc. Online research leads me to think its the BCM. Thoughts? What else can I check/troubleshoot to help zero in on this?

Update: I just got in it and just happen to try to start it and it started but I’m still getting a Hood Open message. Lift gate worked/opened and closed, remotely. Headlights work, brake lights work. I also was able to plug in my OBD reader and it read this time (vs giving ‘error’). It said there were no errors but I went through the erase process anyway. Hood sensor message persists.

Symptoms now are:

-Turn signals do not work.
-Washer fluid pump does not “squirt”, but wipers work.
-Windows work.
-Clock radio reset to noon.
-HVAC (A/C, Heat, blower) doesn’t work at all–no indication from A/C console.
-Turn signals do not work.
-And the worst of all, it’s stuck in park (I rocked the car, turned the wheel, etc.) No good. There is also no little door or button by the shifter for a shifter lockout thingy.

I think you may have several things going on at the same time. Recheck the fuses and connections. Also check you wiring harness where it connects to the battery. Any corrosion present will cause electrical issues.

Turn signal – Two 15 amp fuses LT/TRN/SIG, RT/TRN/SIG

Radio is reset because you changed the battery so the internal clock was without battery voltage.

Washer pump uses a relay and a 10 Amp Fuse

Shift Lock Solenoid – controlled by BCM

According to research:

Chevy Mechanic: karrs2fix

It sounds like you have a body control module issue, You will need see if you can communicate with the module and be able to scan the module for failure codes , monitor data parameters (input / output command status) . There are technical service bulletins regarding problems with body control module ground circuit causing your issues.

Bulletin No.: 07-08-47-004D

Date: August 17, 2011

Subject: Information on Body Control Module (BCM) Grounds

Models:
2006-2011 Buick Lucerne
2007-2012 Buick Enclave
2006-2011 Cadillac DTS
2007-2009 Cadillac SRX
2007-2012 Cadillac Escalade Models
2008-2012 Cadillac CTS
2006-2008 Chevrolet Monte Carlo
2006-2012 Chevrolet Impala
2007-2009 Chevrolet Equinox
2007-2012 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2008-2012 Chevrolet Express, Traverse
2007-2012 GMC Acadia, Sierra, Yukon Models
2008-2012 GMC Savana
2007-2009 Pontiac Torrent
2007-2010 Saturn OUTLOOK
2008-2010 Saturn VUE
2008-2010 HUMMER H2
Supercede:
This bulletin is being revised to update the models and model years. Please discard Corporate Bulletin Number 07-08-47-004C (Section 08 – Body and Accessories).
The purpose of this bulletin is to inform dealers of an issue that could cause internal module damage to the Body Control Module (BCM).

The BCM may be damaged when the module is supplied with battery power and the ground path is removed. You must remove the negative battery cable first before removing a BCM ground.

Issue 1

Below is a list of vehicles and the components that the BCM ground path passes through. The negative battery cable must be removed when removing the components noted below.

– 2007 Cadillac Escalade (Left instrument panel junction block)
– 2007 Chevrolet Avalanche, Silverado, Suburban (Left instrument panel junction block)
– 2007 GMC Sierra, Yukon (Left instrument panel junction block)
– 2008-2010 HUMMER H2 (Instrument panel electrical center)
– 2008-2010 Saturn VUE (I/P splice pack)
Issue 2

It is important to note when removing a ring terminal ground, splice pack connector, or inline harness connector for all the vehicles listed in the model section above, that it doesn’t include a BCM ground path. You must remove the negative battery cable if you determine that it is a BCM ground path.

As an 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

Resource: 2009 chevy traverse stuck in park