2011 Tahoe/New introduction and help wanted post.

[Savageshooter]

Hello everyone. I have been lurking for a while, sorry not trying to be a creep, and I finally joined so I could make this post. I am looking for some help or advice before I pull the trigger on more parts.

The vehicle-2011 Tahoe LTZ approx. 185k miles. Vehicle in great shape. My fiance purchased from a family looking to upgrade due to having more children.

The issues- yes I said issues plural, started with the dreaded not able to fill with fuel at the pump. I took off the evap lines at the charcoal canister and pellets everywhere. I changed that still no fix, long story short and a few thousand cusswords later I dropped the fuel tank, went ahead and changed the fuel pump it's around 185k miles. While not showing any symptoms at the time i figured it was a good choice. Went back in with and OEM Delco module and no issues there. Blew all the evap lines out,alot more pellets came out. Discovered pellets in the tank. Cleaned that out. Started to get a p0455 code for evap system leak. Change the purge valve solenoid that's under the hood. That code went away so I assumed it fixed. So the evap issues out of the way my fiance would randomly get a c0561 chasis code for brake boost sensor a/b correlation. I change that sensor out and that problem was cleared up. The issues is randomly we will get the vehicle going into a stall almost whe. You try to apply power. It sputters and shutters, tsc light comes on and it sometimes throws a code for p0507, sometimes nothing but the tsc light will flash. I hate to think the pcm or ecm is going bad but I have been scratching my head at all the random codes that pop up now. So as of today it has a crankshaft position sensor. I purchased a smoke machine to search for vacuum leaks to no avail. I have even smoked the brake booster to see if it has a bad check valve and it's solid. I am sure I am leaving out details that could jeep solve this mystery so any help is appreciated. I swear it seems to be some random electrical issue or the pcm or ecm is giving fits. Thanks for the help and sorry for the long post.

 

[Miami-Dade]

@Savageshooter Moved you here from intro section for your issues.
Welcome from Miami&Queens NY!

 

[tooleyondeck]

Welcome from FL! I also crept the forums before finally joining lol.

I would start with the simplest (and cheapest) thing first: check all of your grounds

 

[Fless]

Welcome from the Centennial State!

 

[Hoesgottaeat2]

Welcome from NY!

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

As stated above, check and clean all grounds, including the ground on the truck's frame under the driver's position. These trucks are very sensitive to corroded grounds.

 

[dkad260]

The suggestions on the ground wires/locations are definitely good. The best way to think about it is, if the circuit has a bad ground, it will look for a ground elsewhere, whichever has the least resistance. This is where the problems start.

As far as stalling under load....

Have you checked the air filter for a rodents nest? How old are the O2 sensors (likely not related)

Clean MAF sensor?

Are there any other stored codes?

I doubt anything made it upstream of the fuel filter but wouldn't hurt to verify adequate fuel pressure at the rail...not sure what it should be but wanted to toss that in.

Pull your evap line just after the throttle body, the one facing upwards, see if you have any of the debris from the canister in the line.

If your P0507 code started after your tangle with the evap system, maybe you have a line disconnected or a broken/cracked fitting along that system.

Has anyone tried to clean the throttle body? Sometimes harsh chemicals can enter the throttle arm if wrong cleaning agents are used.



Do you have a high idle or normal?

 

[Savageshooter]

Hey thanks for that. Could anyone tell me w

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

As stated above, check and clean all grounds, including the ground on the truck's frame under the driver's position. These trucks are very sensitive to corroded grounds.

 

[Savageshooter]

Sorry for the jumbled up reply. I have checked and cleared the evap codes. I replaced the throttle body due to the high idle and the code it threw. Sorry I don't remeber the code number. It is just odd that I fix one thing and another throws a code. Not saying that it couldn't be possible but this many things it thinks is going wrong seems really odd to me.
I'll start with the grounds. Does anyone have a list,number, and location of these that I should check? That would be greatly appreciated. MAF is clean and in good shape. The air filter is also clean ish and the box is rat/mouse free. I will post some pictures this evening. And again, thank you all for the replies and some thoughts on what to check next.

 

[Savageshooter]

The suggestions on the ground wires/locations are definitely good. The best way to think about it is, if the circuit has a bad ground, it will look for a ground elsewhere, whichever has the least resistance. This is where the problems start.

As far as stalling under load....

Have you checked the air filter for a rodents nest? How old are the O2 sensors (likely not related)

Clean MAF sensor?

Are there any other stored codes?

I doubt anything made it upstream of the fuel filter but wouldn't hurt to verify adequate fuel pressure at the rail...not sure what it should be but wanted to toss that in.

Pull your evap line just after the throttle body, the one facing upwards, see if you have any of the debris from the canister in the line.

If your P0507 code started after your tangle with the evap system, maybe you have a line disconnected or a broken/cracked fitting along that system.

Has anyone tried to clean the throttle body? Sometimes harsh chemicals can enter the throttle arm if wrong cleaning agents are used.



Do you have a high idle or normal?

Hello, I did check fuel pressure and verified that it is good and holding as it should as well. The only stored or permanent codes is the one for brake boost sensor correlation A/B, and the crankshaft position sensor. But I've had a lot of codes that I'll fix or replace a part and something else comes up.

 

[Savageshooter]

Hello everyone who might still be around. I did happen to replace the negative ground cable. Which btw is a huge pain in the tail! I had to remove half the bumper to get to the front wire. Man what were they thinking. Anyways, still having issues. I assume there would be other grounds? Anybody know where the others are located? Also, I have a picture of what the vehicle does. Just sitting at idle in a drive through line, rpms start acting weird, vehicle nearly stalls unless you give her a little gas along with the brake. Then we get what's in the picture. Not sure what's causing it to snap and throw this code or put it in this mode. Any thoughts would be appreciated.

 

[bobby2175]

So, I lived this nightmare on electrical - almost got rid of the truck because of all the money I spent with dealers with minimal success (think $4,000 replacing expensive parts of the electrical system) - until I found this site and a few other videos. What I found is that the dealer was just following DTCs and then replacing parts - that doesn't work here. I could have solved all of this for around $100 and very little of my time!

Your issues are manifesting similar to mine, but not exactly the same. The service stabilitrak and almost stalling are common threads and makes me think you need to go deeper into electrical like others have said.

1. Start here and don't skip this step. Make sure your battery is in good shape - have it tested
2. Clean up the terminal contact points, cable contacts at the battery including the 175 mega fuse.
3. You've already replaced the negative cable (which solved my problem)! Make sure you not only reattached that hard to reach ground behind the bumper, but that you clean up the contact points. I peeled back the wheel shroud and reached through to get to that ground. You can't actually see it - you have to do it blind and then confirm with your phone camera. It's ideal for someone like you that knows how to remove the bumper as you will then have great access and can do a thorough clean job at that point.
4. There are two grounds on the frame below the driver's seat - very easy to access - you hardly have to get under the vehicle.
5. There is a ground strap that goes from the firewall to behind the engine. Inspect that strap. You cannot really access the point behind the engine. If that strap looks to be in bad shape, you will need to create a new ground for it. I haven't gotten here yet, but will when I do big 3/4.
6. There is also the positive battery cable that goes from the battery to the under hood fuse block on the driver's side. I've heard of people having issues with this cable although my issues don't seem to be from here. It's an easy cable to access. I'd pull that cable, check the contact points at the fuse block (also easy to remove, clean and reseat). I have not yet replaced the cable, but if I was still having issues after everything else, I'd go there. I had already purchased the new cable and a new fuse block out of frustration on these issues and was going to do a full swap of everything until that negative cable solved my issues
7. I've been applying a thin layer of dielectric grease at each location I've been cleaning up
8. There are some additional grounds up front in and around the dash/pillars, but I have not gotten here yet.
9. I've learned that part of routine vehicle maintenance for this truck is making sure the grounds are in good shape.

Let me know if you need any pics or videos. I did a lot of research along the way, but it seems like you know a lot more about cars than I do!

Don't give up on this like I almost did. I love my truck again after getting help from everyone here, having now driven about 2,000 miles with no issues, and now having enough confidence to take the truck down to Florida from Michigan next month with the family - that's saying a lot after almost 5 years of electrical issues that made the truck not driveable and it spent a lot of time in the garage.

 

[alpha_omega]

I’d say that @bobby2175 (hopefully) hit the nail on the head for your issue.

If you look up “Big 3 Battery Cables” you should find plenty of threads pertaining to this fix - what size and style of wires to use, which wires need replaced, which wires go where, what can be reused, where new ones need to be added.

If you have already properly cleaned the throttle body and MAF sensor, and checked all of your plugs and plug wires, then your next step would be an overhaul on the battery cables. Let us know your results once you get those cables (and possibly a fresh battery if needed) swapped out. By chance if cleaning the throttle body and installing new wires doesn't fix your problem, then there are a couple other things that could be the issue. However, chances are it’s the weak power and ground wiring these vehicles have. Best of luck, let us know if you have any issues /questions and keep us posted of your results.

 

[Doubeleive]

I will just say that at 185k you should expect to experience some failures, the dreaded 160k+ mile mark is when things will need to be addressed if they haven't already left the party
things like
heater hose T's & heater hoses
water pump
radiator
alternator
maf
throttle body
transmission
front differential
front wheel hubs
control arms
ball joints
bushings
tie rods
if there is rust
then add brake lines and any modules attached under the vehicle and any exposed wires

these are just typical things due to the mileage, they may happen one at a time or all at once, this is often why people decide to sell them at this mileage rather than invest money into fixing it.

this is just the way it is.... so don't get discourged once you have a good baseline of what has been addressed you will be good for a long time.

 

[bobby2175]

For reference, here are all of the codes my truck was throwing on 1 day (3/21/22) when I had the electrical gremlins and had the truck in the dealer - C0242, C0561, C0590, C0615, C0895, P069E, P0700, U0073, U0100, U0100, U0101, U0121, U0140, U0170, U2100 - only 3 were history.

 

[Doubeleive]

For reference, here are all of the codes my truck was throwing on 1 day (3/21/22) when I had the electrical gremlins and had the truck in the dealer - C0242, C0561, C0590, C0615, C0895, P069E, P0700, U0073, U0100, U0100, U0101, U0121, U0140, U0170, U2100 - only 3 were history.

when you get a bunch of random codes that is a clear indication that there is a bad ground or an interuption in the lan bus, like a shorted wire or broken wire or wire touching another wire
you can try and find it by feeling all the wires, lift them up and run your fingers over them and feel for any cracks, pinched harness, rubbed spot, use a flashlight look everything over, typically when the wires are resting on something that is where they will rub thru or break

 

[Savageshooter]

So, I lived this nightmare on electrical - almost got rid of the truck because of all the money I spent with dealers with minimal success (think $4,000 replacing expensive parts of the electrical system) - until I found this site and a few other videos. What I found is that the dealer was just following DTCs and then replacing parts - that doesn't work here. I could have solved all of this for around $100 and very little of my time!

Your issues are manifesting similar to mine, but not exactly the same. The service stabilitrak and almost stalling are common threads and makes me think you need to go deeper into electrical like others have said.

1. Start here and don't skip this step. Make sure your battery is in good shape - have it tested
2. Clean up the terminal contact points, cable contacts at the battery including the 175 mega fuse.
3. You've already replaced the negative cable (which solved my problem)! Make sure you not only reattached that hard to reach ground behind the bumper, but that you clean up the contact points. I peeled back the wheel shroud and reached through to get to that ground. You can't actually see it - you have to do it blind and then confirm with your phone camera. It's ideal for someone like you that knows how to remove the bumper as you will then have great access and can do a thorough clean job at that point.
4. There are two grounds on the frame below the driver's seat - very easy to access - you hardly have to get under the vehicle.
5. There is a ground strap that goes from the firewall to behind the engine. Inspect that strap. You cannot really access the point behind the engine. If that strap looks to be in bad shape, you will need to create a new ground for it. I haven't gotten here yet, but will when I do big 3/4.
6. There is also the positive battery cable that goes from the battery to the under hood fuse block on the driver's side. I've heard of people having issues with this cable although my issues don't seem to be from here. It's an easy cable to access. I'd pull that cable, check the contact points at the fuse block (also easy to remove, clean and reseat). I have not yet replaced the cable, but if I was still having issues after everything else, I'd go there. I had already purchased the new cable and a new fuse block out of frustration on these issues and was going to do a full swap of everything until that negative cable solved my issues
7. I've been applying a thin layer of dielectric grease at each location I've been cleaning up
8. There are some additional grounds up front in and around the dash/pillars, but I have not gotten here yet.
9. I've learned that part of routine vehicle maintenance for this truck is making sure the grounds are in good shape.

Let me know if you need any pics or videos. I did a lot of research along the way, but it seems like you know a lot more about cars than I do!

Don't give up on this like I almost did. I love my truck again after getting help from everyone here, having now driven about 2,000 miles with no issues, and now having enough confidence to take the truck down to Florida from Michigan next month with the family - that's saying a lot after almost 5 years of electrical issues that made the truck not driveable and it spent a lot of time in the garage.

Hi Bobby and thanks for the details and information. I'll be certain to check these grounds and the other positive cable. I replaced the cable that is the main battery + clamp that has the alternator cable and the other cable you mentioned bolted to it. This cable just ran to the starter so I will be sure to check those other cables. The one going to the alternator looked fine and is the easiest. The grounds I will go over those very carefully. I suspect there is something with this as well. I cleared all my codes yesterday and drove the vehicle with the traction control and stabilitrak turned off on my way to work. I drive about 20 ish miles one way. I checked for my abs correlation code and it hasn't shown back up yet. My plan is to drive the vehicle and get as many miles on it until it starts to show up again. It has typically been many miles before it shows up. Say maybe 200 miles since codes being cleared before it shows any issues. Again, I will go through all these cables and begin the process of checking and verifying.

Thank you for the help.

 

[bobby2175]

This sounds so much like what I went through. I'd go 100s of miles and then it would show up. I turned traction control off in hopes that would do it - it all failed. Spend the time on the cables and I'm hoping it takes care of it!

 

[alpha_omega]

Reviving an old thread - Did you ever find the culprit to your issue (bad grounds, brake pedal sensor), or at least narrow it down to one or two potential issues that you’ve since corrected?