2008 Yukon Denali - $3000 dollars in repairs and I still have P0171 and P069E DTCs.

[Doubeleive]

I've had it with this 2008 Yukon There's no fixing it at all. I'm stripping out all the new parts I put into this issue, returning them all for my money back and sending off the crusher at this point.

I have gone through a total of 7 defective out of the box GM OEM fuel pumps from the dealership, 3 of them today. Every single one had insufficient fuel pressure or some other issue that caused the same problems.

I have replaced and verified all the associated wiring harnesses and electrical grounds.

I have replaced the whole computer system and every related module we could think of including the FPCM. We reflashed the computer five times.

I have replaced the fuel rail pressure sensor.

After multiple extensive and expensive diagnostics by the best mechanics that can be found here all found no reason whatsoever for this to be constantly throwing P0171 and P069E other than the possibility that you can't get a fuel pump that works for this vehicle. They went over this vehicle from top to bottom and found absolutely no reason for these codes to keep popping up. Everything absolutely possible has been done and still the same results and no one can figure it out other than the possibility that every single fuel pump is bad from the factory.

Every mechanic, including the service managers at 4 different dealership advised to just junk it because it will only get worse because you simply can't get replacement parts that will work at any price.

At this point, I don't want to even try one more fuel pump because it'll just be another defective from the factory part because all indications is that it will just be another waste of time. I have simply run out of any and all possible and even impossible solutions to fix this problem. I never thought a new fuel pump would turn into a never ending recurring nightmare like this. This is clearly a problem that will never be solved because no one can figure it out and I can't afford to drain my bank account any more than I already have.

It's a shame because the vehicle is in pristine condition inside and out and I am left with no choice but to strip it clean and what no one will buy from it will go strait to the crusher. Unless someone else has an idea, it's getting junked. The frustration meter is pinned.

MEH, throw a Auxiliary fuel pump on it and drive it
@randeez can point you to one that will work

 

[mikez71]

What? The ECM reset didn't work?

And how did you go from 4 new pumps to 7 in a day?

This is a depressing thread if no resolution.

 

[SpareParts]

Bad grounds?

 

[Gildan]

MEH, throw a Auxiliary fuel pump on it and drive it
@randeez can point you to one that will work

The only problem with that is that the required volume of the fuel being delivered at that pressure is controlled by the FPCM driving the speed of the fuel pump and it will cause a lot of other issues that won't be able to fixed.

 

[Gildan]

What? The ECM reset didn't work?

And how did you go from 4 new pumps to 7 in a day?

This is a depressing thread if no resolution.

What? The ECM reset didn't work?

And how did you go from 4 new pumps to 7 in a day?

This is a depressing thread if no resolution.

I switched out three (3) new pumps today and each one was in varying states of non-functionality. Can you imagine dropping the same fuel tank and replacing the pump three (s) times in one day and replacing all the modules that appear to be fine with brand new ones and get the same exact results every single time? I can.

It's very depressing when 7 GM OEM fuel pumps are defective right out of the box, one after the other. But that's the current state of 'enshittification' the world is in. All the replacement parts are garbage and the manufacturers have no quality control and they don't care anymore.

 

[dkad260]

Are these fuel systems designed to have a continuous return flow to the tank? If so, are you getting fuel drained back to the tank? Would a purge valve or solenoid cause these issues? It sounds like maybe the evap system is performing a vacuum test on the tank for holding pressure 30 seconds after startup but maybe a line was connected wrong or damaged when the tank was lowered. Not sure how this would coincide with a pressure drops but look back at the timeline ....all was working fine until you lowered the tank and removed the pump.

Did something get snagged when lowering the tank?

Is something getting pinched when you raise the tank?

 

[Gildan]

He did say he checked pressure with a mechanical gauge.
I agree, 4 faulty pumps in a row seems as unlikely as anything else.. The dealerships should have to re-imburse you if that's the case.

Particularly the fact that they pop codes in such a precise timeframe.. (which makes the sensor seem unlikely as well)

If you do have a P0171, that shouldn't be caused by the fuel pump, or it should affect both banks?

And if I had 4 bad OEM pumps in a row, I don't think I'd go with OEM next time around!

Weird!
Looking forward to the confirmed fix!

I replaced the sensor a couple of hours ago to see if that was the problem and it was not. In fact, it made it worse. I put the old sensor back in and it got even more worse. All the live data confirms the sensor is working correctly, the ECM, BCM, FPCM, etc., etc., etc., have literally been replaced and the same thing is happening. I even replaced the charcoal canister, and all the other emissions goodies and it still does the same thing. I even went so far as to check for vacuum leaks and even replaced the MAF sensor. Nothing improved or even changed except for the worse. Several mechanics have just given up. No one can figure out a fix, $3000 later and nothing.

 

[Gildan]

Are these fuel systems designed to have a continuous return flow to the tank? If so, are you getting fuel drained back to the tank? Would a purge valve or solenoid cause these issues? It sounds like maybe the evap system is performing a vacuum test on the tank for holding pressure 30 seconds after startup but maybe a line was connected wrong or damaged when the tank was lowered. Not sure how this would coincide with a pressure drops but look back at the timeline ....all was working fine until you lowered the tank and removed the pump.

Did something get snagged when lowering the tank?

Is something getting pinched when you raise the tank?

No, this Yuke uses a returnless system. The evap system has absolutely no faults. In fact, everything is within specs except the fuel pump pressure (and I keep getting defective OEM pumps right out of the box one after the other). I ordered yet another fuel pump that is claimed to have been bench tested for proper performance. If that one doesn't work, the person who sold it to me will have to extract it from their throat via their ******.

I swear, if I drop this tank for the 8th time and the new pump is defective, I am going to drive it out to the rifle range and turn it into swiss cheese with a BAR. And I'm not joking.

 

[dkad260]

Do both codes pop up at the same time, or one before the other? Have you done a vacuum test on the evap lines?

Usually if you have a failed tank vacuum test, then it will throw an evap code. However engine vacuum is required and you have the P0171 code which could be an intake manifold gasket, throttle body gasket, or a damaged vacuum hose. The code I believe is thrown when you have to add more fuel to compensate for the lean condition.

Perhaps the mechanic is seeing the P0171 code as a lack of fuel issue and not an air issue. If you are sucking in unmetered air, the O2 sensors will see this and ask for more fuel....throwing a lean code. That doesn't mean you are starving of fuel, it means you are compensating for a lean condition.

Just an idea but doesn't explain the other code.....unless it's sucking in a ton of air and can't keep up at idle.

I'm starting to lean (no pun) towards a bad vacuum line, vacuum leak....did you double check the throttle body gasket?

 

[Gildan]

Are these fuel systems designed to have a continuous return flow to the tank? If so, are you getting fuel drained back to the tank? Would a purge valve or solenoid cause these issues? It sounds like maybe the evap system is performing a vacuum test on the tank for holding pressure 30 seconds after startup but maybe a line was connected wrong or damaged when the tank was lowered. Not sure how this would coincide with a pressure drops but look back at the timeline ....all was working fine until you lowered the tank and removed the pump.

Did something get snagged when lowering the tank?

Is something getting pinched when you raise the tank?

Nope. Everything is as it should be. It started when I replaced a fuel pump that was leaking out the top and pouring gasoline all over the ground. All I did was switch out the original OEM pump for a brand new OEM pump. Nothing changed except the pump which turned out to be bad right out of the box.

Our local mechanics are now seeing a lot of this exact problem popping up in the past few says or similar fuel system problems that simply cannot be fixed no matter what is done. They thing the 20% - 25% ethanol in all grades of gas around here is doing irreparable damage to everyone's vehicles and I am beginning to agree with them. And if you think State governments would have a fit when they test the fuel at gas stations and do something about it, they just look the other way and do nothing from what I can see.

 

[Gildan]

Do both codes pop up at the same time, or one before the other? Have you done a vacuum test on the evap lines?

Usually if you have a failed tank vacuum test, then it will throw an evap code. However engine vacuum is required and you the P0171 code which could be an intake manifold gasket, throttle body gasket, or a damaged vacuum hose. The code I believe is thrown when you have to add more fuel to compensate for the lean condition.

Perhaps the mechanic is seeing the P0171 code as a lack of fuel issue and not an air issue. If you are sucking in unmetered air, the O2 sensors will see this and ask for more fuel....throwing a lean code. That doesn't mean you are starving of fuel, it means you are compensating for a lean condition.

Just an idea but doesn't explain the other code.....unless it's sucking in a ton of air and can't keep up at idle.

I'm starting to lean (no pun) towards a bad vacuum line, vacuum leak....did you double check the throttle body gasket?

 

[dkad260]

You didn't by chance fill up with E85 did you? Assuming you don't have a flex fuel vehicle.

 

[Gildan]

Do both codes pop up at the same time, or one before the other? Have you done a vacuum test on the evap lines?

Usually if you have a failed tank vacuum test, then it will throw an evap code. However engine vacuum is required and you have the P0171 code which could be an intake manifold gasket, throttle body gasket, or a damaged vacuum hose. The code I believe is thrown when you have to add more fuel to compensate for the lean condition.

Perhaps the mechanic is seeing the P0171 code as a lack of fuel issue and not an air issue. If you are sucking in unmetered air, the O2 sensors will see this and ask for more fuel....throwing a lean code. That doesn't mean you are starving of fuel, it means you are compensating for a lean condition.

Just an idea but doesn't explain the other code.....unless it's sucking in a ton of air and can't keep up at idle.

I'm starting to lean (no pun) towards a bad vacuum line, vacuum leak....did you double check the throttle body gasket?

All that has been checked and there is nothing wrong with evap system. P0191 abd P069E are the only codes being thrown simultaneously after simultaneous provisional codes for the same thing are thrown. Those are the only codes. Then performance deteriorates and the only thing that can be done to temporarily fix the problem is to pull the ECM fuse for 10 minutes and the problem goes away for about an hour. But the codes are thrown simultaneously exactly 30 seconds after the motor starts. Exactly 30 seconds. And nothing in the live data other than low fuel pump pressure data shows. The only logical conclusion is that ever single fuel pump I have put in is defective right from the factory. Every single one of them. One after the other. Defective. Every GMC vehicle I have ever owned has spent more time in the shop than on the road and I'm not joking about that.

The old failing pump was not throwing any codes at all, it just rusted out on top and spilled gas all over the place. I put in a brand new pump and that's when the problem started. I'm about ready to just junk an otherwise pristine vehicle. There are so many interlocked systems on this vehicle that one problem causes a myriad of other unrelated issues with no clue where to start. And the process of fixing vehicles is to simply start replacing parts until the problem goes away or you go bankrupt in the process. One thing for sure is that I will never buy a GMC/Chevy ever again, new or used. They are junk that simply cannot be fixed when something goes wrong and if they can be fixed, you might as well have saved yourself money by going out and buying another vehicle that will do the same thing to you. It's getting to the point that if a wiper blade or headlight goes out, get rid of the vehicle because it's either impossible to service or it's too expensive to fix.

 

[Gildan]

You didn't by chance fill up with E85 did you? Assuming you don't have a flex fuel vehicle.

Nope. It's not a flex fuel and I didn't put E85 in it. The vehicle is just a piece of junk from the get go.

 

[Gildan]

OH! I just figured out what is wrong here!

I looked up the part number for the pump to see which vehicles use this particular pump. They have been giving me the pump for a 2007 and earlier Yukon. The 2008 Yukon use different pump and the ones for the 2007 are not compatible.

 

[mikez71]

Well your mechanics and dealer aren't very good if they couldn't get that right...

Fingers crossed...

 

[dkad260]

Before you drop the tank again, verify the ethanol content from the scan tool.

What are your LTFT's at idle? If 15% or more, that might point to a vacuum leak.

Get it on the road and select a gear where you can cruise at 2000-2500 RPM under a load and see what the Long Term Fuel Trims look like. Are they increasing or working back down towards 0

If they are increasing, I would suspect a fuel delivery issue...if they are reducing then you likely have a vacuum leak resulting in unmetered air...and not a pump issue.

 

[Doubeleive]

OH! I just figured out what is wrong here!

I looked up the part number for the pump to see which vehicles use this particular pump. They have been giving me the pump for a 2007 and earlier Yukon. The 2008 Yukon use different pump and the ones for the 2007 are not compatible.

may not be what you want to hear but all these pumps and you never verified the part number?
I don't walk out of a dealer parts or auto parts without making 100% sure I have the right part and that it matches the part number on the box and is indeed the one I need.
In the case of a dealer it is done via the last 8 of the vin.

 

[Gildan]

Well your mechanics and dealer aren't very good if they couldn't get that right...

Fingers crossed...

I went directly to the OEM manufacturer site and looked up what vehicles the pumps the dealership was giving me went to - they were the pump designed for a 2007 and earlier Yukon which is not compatible with the 2008 and later.

The 2008 and later Yukon with the 6.2 motor use a different pump with substantially different specs and different electronic internals. Using the wrong pump that the dealership sold me was specifically noted to cause the exact same problems I am having now. And there is absolutely no way the dealership could not have know this unless they are total incompetents.

Just wait until I get ahold of those morons in the morning. I will wring their collective necks.

Before you drop the tank again, verify the ethanol content from the scan tool.

What are your LTFT's at idle? If 15% or more, that might point to a vacuum leak.

Get it on the road and select a gear where you can cruise at 2000-2500 RPM under a load and see what the Long Term Fuel Trims look like. Are they increasing or working back down towards 0

If they are increasing, I would suspect a fuel delivery issue...if they are reducing then you likely have a vacuum leak resulting in unmetered air...and not a pump issue.

I figured it out. I looked up the part number for the pumps that they gave me and guess what, they gave me the wrong pump. The pump they gave me was for the 2007 and earlier instead of the one for the 2008-2014. There's a very explicit warning that the 2007 pump they gave me will not work on a 2008-2004 and will produce the same exact codes and issues I am getting.

The worst part is that they are so negligent to not even look at the specific details and warnings for the pump they sold me and it's right there in big bold red letters with a warning symbol about this very same issue. They are either morons or they are deliberately malicious. 7 wrong pumps in a row. I am fit to be tied.

99% of the problems are caused by stupid people. I think we take the warning labels off of all consumer products and let the stupid people self-eliminate.

 

[dkad260]

Wow. The VIN should depict that you have a 2008, unless they looked at the door sticker and saw a 9/07- 12/07 and thought it was an 07.

That's crazy, hopefully this will fix it.