"Hood open" sensor warning and the car will not start and OBDII reading gives Error

Tiny
DANTHEMANT
  • MEMBER
  • 2009 CHEVROLET TRAVERSE
  • 3.6L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 150,000 MILES
Okay, I've got a good one for you. My vehicle listed above 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 6 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 okay, but then drained 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 battery). 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" position, I've noticed the A/C doesn't work, 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 visual 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 duel level but when I last drove it, I filled it to expel any air in the tank, 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 to reset TPS and other intermittent codes e.G, catalytic converter used to throw a code every other month or so, etc.) Thoughts? What else can I check/troubleshoot to help zero in on this?
Monday, May 24th, 2021 AT 10:52 AM

29 Replies

Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
Here's what it does when I insert the key and then turn to 'on, then to 'start'.
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Monday, May 24th, 2021 AT 10:55 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

By any chance, could mice have gotten to the vehicle while it was parked? I ask because they like the wiring insulation. Also, does the starter engage or does nothing happen when you try starting it? Does the scanner power up when connected?

If the scan tool won't power, check pin 16 at the DLC to see if there is 12v. It should have power at all times, so let me know.

Next, I want you to check the PCM fuse and two ECM fuses under the hood in the fuse box. I attached a pic below showing their locations.

In addition to checking the condition of the fuses, confirm there is power to and from them. Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Let me know if the starter engages or not. And, don't laugh, but let me know if the vehicle may have had mice get into it. You would be amazed at what damage they can do. So, check the wiring at the hood switch and trace it back. It may no longer be connected causing the light to be on.

One last thought. Does the new battery go dead if you allow it to sit for a few days?

Let me know.

Joe

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Tuesday, May 25th, 2021 AT 8:38 PM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
Joe,

First and foremost, thank you very much for your assistance! I suspect you guys don't hear that enough.

No chance or sign of mice but I have had a rare leak from what I suspect to be a poorly sealed replacement windshield a few years ago or maybe the sunroof. Water damage may be (and probably is) a factor.

I can jumper the CRNK relay to engage the starter, so I know the starter works. I did this when I recently had to replace the ignition switch on the column (to test the starter/motor).

The scan tool powers and acts normally, like it is reading, but results in 'error'. I visually checked all the fuses and none appear to be blown but I did not go so far as to check them or any contacts with a continuity/multimeter.

The new battery is, well, too new. If there is a parasitic drain I might not know for maybe a week. I just put in the new battery about 3 days ago.

Other functions work but I'll go check the fuses right now.

Update: I got in 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.

After the above, I didn't even pop the hood.
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Wednesday, May 26th, 2021 AT 9:55 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

Do the brake lights work? I'm asking because that is what sends a signal to the body control module to release the park lock actuator.

What is going to make this a little difficult is all of the affected items have different power sources. The one thing that controls most is the body control module (BCM). It's under the dash on the right side. If you have a water issue, that could be the problem.

I need you to bear with me. I need to start with the power supply. If you look at pics 1 and 2, they are related to the underhood fuse box. I need you to check the fuses I highlighted. Also, confirm there is power to them.

Pic 3 shows the fuse box in the vehicle. Check the BCM fuse I highlighted. Again, even if the fuse appears good, make sure there is power to and from it.

The last two pics are the wiring schematic for the starter. There is a white wire which travels from the ignition switch to the BCM. That should have power when the key is in the start position. I will need that checked if all fuses are good. Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

What really should be done first is to scan the CAN bus system. CAN stands for controller area network. Basically, all modules/computers are tied together via a few wires. When you use a traditional scan tool, most only look for engine trouble codes. If you use a scan tool able to read all codes, it will identify where the breakdown is.

Here is a video showing it being done:

https://youtu.be/InIlnsjOVFA

Since the new ignition switch was installed, it could even be a loose connection at that point, so you may want to check that as well.

The last pic below indicates the location of the BCM, under the dash on the driver's side. See if there is any evidence of water damage.

Let me know what you find.

Joe

See pics below.

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Wednesday, May 26th, 2021 AT 5:53 PM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
Joe,

Thanks for the diagram--very helpful! I couldn't find a pic or diagram of the BCM location anywhere. Everything you advised to check checks out. No obvious signs of water damage or water at all, no stains, nothing feels remotely wet or damp. Wires and wiring harnesses look almost like new. No blown fuses, power supply and continuity checks out.

My listed symptoms above persist except now I've noticed that my hazard lights also do not work. As I stated earlier my brakes lights work, but it's still stuck in park. I'm starting to feel more and more like its the BCM, but I'm no pro.

Will a CAN Bus reader tell me what "parts" of the BCM are (seemingly) faulty, as I am experiencing, or would it just say, "on" or "off" or "ok" for the whole unit?

Dan
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Thursday, May 27th, 2021 AT 12:06 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

If there is an issue with the BCM or communication with the BCM, scanning the CAN should identify a diagnostic trouble code or codes. Often times, the code will start with the letter U rather than the traditional P codes.

If possible, have that done, and let me know the results.

Take care,

Joe
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Thursday, May 27th, 2021 AT 7:54 PM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
It's not possible as I would have to either tow the vehicle (being currently stuck in park) or buy the CAN Bus reader, which is around $450.00 on Amazon. While I see this as a good investment being far more capable then my simple OBD reader/eraser, I've decided to financially gamble and go with a rebuilt/reprogrammed BCM. I found a place that will take my VIN and pre-program it (highway71autoparts) so that it will hopefully be plug-n-play and get me out of park. The guy I spoke to at Highway71/Deerings said that in rare cases the airbag may have to be "re-assigned". That is something I do not know how to do, if it occurs. Could my little OBD scanner reset the airbag code or do you know if the Autel MaxiCom MK808 could do that (if I end up needing it)?

P.S. I will definitely follow up here after I get my BCM installed.
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Friday, May 28th, 2021 AT 7:46 AM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
Autel Tech support says the MK808 is not able to reassign the airbag and that I would need "a high-end tablet" to do that, which I interpret to mean a higher/more capable software-based diagnostic tool typically at the dealer. If I do run into this airbag problem and cannot get resolution through hwy71, I doubt the dealer will be cooperative in performing this on a rebuilt BCM.
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Friday, May 28th, 2021 AT 7:51 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

Let's hope this takes care of the problem. I attached the directions below for the replacement of the body control module.

Let me know if you have other questions.

Take care,

Joe
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+1
Friday, May 28th, 2021 AT 4:23 PM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
I'll update when I get the replacement unit installed.
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Tuesday, June 1st, 2021 AT 10:40 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Sounds good. I look forward to hearing from you.

Take care,

Joe
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Thursday, June 3rd, 2021 AT 6:54 PM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
Joe,

I swapped out the BCM with the programmed refurbished unit and exact same problems exists (only now with the expected airbag warning light). I'm now at a loss as to what the problem or problems could be. It no longer seems like it may be a single-source issue. I'm beginning to think that when the battery drained and the subsequent efforts to charge it/disconnect/reconnect/jump may have done widespread damage. I'm almost to the point of junking the vehicle or selling/having it towed away. Any other ideas would be appreciated.

Dan
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Wednesday, June 16th, 2021 AT 7:14 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Dan,

Good to hear from you, but not under these conditions. Nothing changed with the new BCM? And just to reconfirm, the white wire which leads to the BCM powers when the key is in the start position, correct?

We are missing something simple. Have you checked the ECM and ECM1 fuses under the hood? If not, do that. In addition to checking the fuse, confirm there is power to them. See pic 1 below.

Also, on the rear of the engine near the power steering pump, there is a ground. It will be bolted to the block. Make sure it's in good condition.

Let me know also if the ignition switch feels differently.

Take care,

Joe
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Wednesday, June 16th, 2021 AT 7:18 PM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
Joe,

I'll check those items this weekend. The ignition switch is the same. Today I worked to test one system--the A/C. I swapped the horn relay with the A/C relay, to see if the A/C would work (because the horn does) and I also tested the A/C fuse--all good, which is to say, no change.

I noticed a new symptom today. The window switches at the driver's door will not operate the rear seats windows, but the front seat windows work. I didn't try the switches on the rear seat doors. This is so weird, how about 1/2 of the "things" in the car don't work, but the other half do. It's clearly not the BCM, IMO. It's hard to think that it could be a ground, with so much stuff working, and while I will test the fuses (and ground), they all look solid against a flashlight. I even looked for sign of mice or rats maybe chewing on wires. Other than being a semi-old car, it looks like everything is in great shape.

Would a more advanced OBD reader tell me anything? If so, could you recommend one (that won't break the bank)?

Dan
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Thursday, June 17th, 2021 AT 1:39 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

If you haven't already, scanning the can-bus may help. If you look online (Amazon) they offer scanners that can read obd2 and can-bus codes starting around $15.00. I can't say how good they would be, but they indicate CAN protocols as well as the standard OBD2 protocols.

I can't guarantee it will help, but if there is a module in the system with a code, it should show up for you.

Joe
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Thursday, June 17th, 2021 AT 9:27 PM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
I have a simple scanner that I got a few years ago from AutoZone for about that price point. It reads for codes and can erase them. Throughout this ordeal, aside from the short period of receiving "error" (as I stated above), I have never received any P codes. I do not know if my unit can read/provide any U codes.

I checked many fuses this last weekend and I simply cannot reach the ground point at the rear of the engine as the vehicle is stuck in park and my driveway is on about a 10 degree slope and I'm not brave enough to block it and jack it up to crawl under it (plus I doubt my wife would permit me to--lol).
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Monday, June 21st, 2021 AT 10:55 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

I don't think I would allow you either. That would be dangerous. Chances are the scanner you have can't read codes other than P type. We need to get our hands on one that can scan the can-bus system. Is there anyone you can think of that can lend one to you?

Joe
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Monday, June 21st, 2021 AT 9:46 PM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
Hey Joe,

I just bought an Autel (MK808) unit on sale for Prime Day. That will tell me more than my legacy reader. Stand by.
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Tuesday, June 22nd, 2021 AT 11:25 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,101 POSTS
Hi,

Sounds good. When you get it, let me know.

Take care,

Joe
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Tuesday, June 22nd, 2021 AT 7:51 PM
Tiny
DANTHEMANT
  • MEMBER
  • 15 POSTS
Joe,

I got the MK808 and spent a good amount of time playing with it (and updating) over the weekend. Before I get into the codes, I replaced the original BCM back (to get rid of the airbag error from the "new"/refurbished BCM), and I replaced the Brake Pedal Position Sensor (as a desperation attempt to get out of park).

I received 9 DTC's but only two systems really "matter" to me: BCM and TCM. Aside from not caring right now about the non-BCM codes (e.G. Driver door switch/motor, memory seat module, etc.), The codes "that matter", after reconnecting the battery, clearing all codes and running diagnostics are:

BCM:
B1395-03 Device voltage reference output 1 circuit low voltage
B1529-03 Device voltage reference output 5 circuit low voltage

TCM:
P0826-00 Up and down shift switch circuit

I don't think the "up and down" shift switch would keep it from coming out of drive, just prevent manual gear shifting.

Also, still no idea why the HVAC will not come on. Switch positions all check as do fuses but first things first, right? Getting out of park.

Dan
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Monday, June 28th, 2021 AT 1:45 PM

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