Dealer not honoring warranty work..2018 5.3 Yukon issues

[LT1ZOB]

Maybe after all this, you're just hyper sensitive like @LT1ZOB. He can hear and smell if you are a potato chip in there a week ago.

come on man, maybe 3 days, 4 tops. But a week is a bit much.

 

[smokey_mountain]

I am on second tank of Exxon Premium Synergy + 93. No difference in my case. With that fuel in tank in the morning on a cold start it missed even at 1200-1500 RPMs. I would like to try all options. When you said you cleaned ground, did you mean ECM ground or battery ground or ground wire to body coupling? I guess where should I try to clean

I solved mine auto stop is working correctly for me

I gained 0.1 volts after a light cleaning the ground wires but they still need a deep cleaning ...





Have you tried higher octane fuel like 91 or 93?(you have to run it for a while to clear out the old 87oct fuel)


don't go to the cheapest station Mobil Exxon or chevron/texco I did notice AFM mode pings a lot with 87 octane even got stuck in the loop of death...

I been to other stations and they charged me 91oct prices for 87 octane ..


noticed after i pumped 9 gallons of the so called 91octane dropped the Timing advancement... by a lot before it was able to advance to upto 42 degrees, after pumping barely able to get to 25 degrees advanced that means my octane dropped to 88 to 88.5octane

View attachment 236247

 

[smokey_mountain]

I did speak with BB guys, they are super friendly and keen to help, but they cannot guarantee that this issue will be mitigated with RPM increase, they have never seen this problem ever before and thus they felt that if the misses/hesitation is there even at higher RPM, it will still be there with tune, I need to work the gremlins out first to get the full benefit of the tune.

I do also wonder if a tune will help you if they raise the idle a tad. My take on the fear of the warranty thing: you already feel like you're screwed on the warranty (at least with this particular concern) and if you're willing to lose $10k trading out of it, that $10k will pay for anything that might not get covered because of the tune. The probability of the tune being looked for anyway is pretty slim. It would really only matter if you had a major failure like the engine throws a rod. I say you have nothing to lose and everything to gain at this point. Blackbear says their tunes are undetectable anyway so I say go for it. A tune made a huge difference on all of my vehicles, I just used a local tuner instead.

 

[smokey_mountain]

While dealers said no codes, I met with another local GM mechanic last night, he drives GM trucks himself, he works on them. He tested the truck and found codes, his theory that these codes point to a different problem rather than themselves amperage with battery, ground or something else. Because there are 3 codes that he saw. There was no Check Engine light for any of them...
B1325
U0415
U0121

 

[wjburken]

While dealers said no codes, I met with another local GM mechanic last night, he drives GM trucks himself, he works on them. He tested the truck and found codes, his theory that these codes point to a different problem rather than themselves amperage with battery, ground or something else. Because there are 3 codes that he saw. There was no Check Engine light for any of them...
B1325
U0415
U0121

View attachment 236401 View attachment 236402 View attachment 236403

What did he recommend as a course of action based on his assessment?

 

[smokey_mountain]

He stored them on the scanner, took photos, cleared them and now wants me to drive for 500 miles and see if any new codes pop up. In 500 miles I have to return to his shop and he will load test the battery and will see if any more codes are popping up on his scanner. If new codes pop up, there is enough evidence to take the truck back to a dealer with the Scanner logs and have them start explaining why codes, what electrical problems and ... why rough idle.

What did he recommend as a course of action based on his assessment?

 

[smokey_mountain]

Interesting observations from last night's 2020 LT 4x4 brand new test drive. Drove the truck for 10 mins at 50+ MPH, came to the stop kept in idle in D and even after a minute in idle look at the idle RPMs - malfunction or ECM still learning?

 

[calif phil]

What’s wrong with that picture? Looks fine to me.


Sent from my iPad using Tapatalk

 

[mikeyss]

What’s wrong with that picture? Looks fine to me.


Sent from my iPad using Tapatalk

Maybe the level of fuel?

 

[Doubeleive]

While dealers said no codes, I met with another local GM mechanic last night, he drives GM trucks himself, he works on them. He tested the truck and found codes, his theory that these codes point to a different problem rather than themselves amperage with battery, ground or something else. Because there are 3 codes that he saw. There was no Check Engine light for any of them...
B1325
U0415
U0121

View attachment 236401 View attachment 236402 View attachment 236403

found this on another site regarding B1325

"I'm a GM World Class Technician and I get nothing but problem vehicles like this. I've worked on a ton of the 2014's with random electrical problems like this. You know what just about fixes them all?.........Battery cables! I replace both positive cables and the negative cable. I bet you if a technician pulls some DTC's they'll find a bunch of B1325 in a lot of modules. The code will be a low battery voltage code. Basically, there is high resistance in the cables not allowing the full battery voltage to come through, so when a module gets around 9-10 volts instead of 12-14, it does crazy stuff. I would also change the battery a well. I'm almost confident this will correct the concern".

 

[smokey_mountain]

Thank you, I definitely now have electrical problems too B1325, U0415, U0121 were cleared but now vehicle has C0800, it all points that after last service some electrical connections were impacted... On top of my rough idle I now have electrical connections that are impossible to troubleshoot. I am taking it in on Tue again to address idle and to address now electrical. This truck is a royal pain...

 

[swathdiver]

Thank you, I definitely now have electrical problems too B1325, U0415, U0121 were cleared but now vehicle has C0800, it all points that after last service some electrical connections were impacted... On top of my rough idle I now have electrical connections that are impossible to troubleshoot. I am taking it in on Tue again to address idle and to address now electrical. This truck is a royal pain...

Are these fresh codes? Do you have a subscription to AllDataDIY? If not, why don't you sign up for one and check out these codes. Mine has some of them and they all point to a voltage problem which is usually a bad battery with a faulty cell. If we've all learned on thing on these forums with these trucks, a bad battery can cause all kinds of grief and mischief with the electrical system. Kinda like that guy Chaos on those car insurance commercials!

 

[smokey_mountain]

@swathdiver thank you, I wanted to ask for your help if possible with fuel trim data, I am seeing my LTFT all negative most of the time, I was wondering if the trims are OK or not (logs are here) https://docs.google.com/spreadsheets/d/1EbdAtrKXjTG0ujUXM6MsoTJqLzYeno1C82mWw76OVsE/edit?usp=sharing

As for electrical (5-6 codes appeared there after truck was from the dealer 12 days ago), no codes before
Codes found and cleared:
B1325 Control Module Power Circuit Voltage below Threshold
B127E Front Video Display Output Signal
U0121 Lost communication with Electronic Brake Control Module, Test Failed
U0401 Invalid Data Received from Engine Control Module
U0415 Invaid Data Received From Engine Control Module
Code found not cleared
C0800 Device power #1 (low current#1) circuit malfunction

Are these fresh codes? Do you have a subscription to AllDataDIY? If not, why don't you sign up for one and check out these codes. Mine has some of them and they all point to a voltage problem which is usually a bad battery with a faulty cell. If we've all learned on thing on these forums with these trucks, a bad battery can cause all kinds of grief and mischief with the electrical system. Kinda like that guy Chaos on those car insurance commercials!

 

[91RS]

Battery cable(s).

 

[swathdiver]

@swathdiver thank you, I wanted to ask for your help if possible with fuel trim data, I am seeing my LTFT all negative most of the time, I was wondering if the trims are OK or not (logs are here) https://docs.google.com/spreadsheets/d/1EbdAtrKXjTG0ujUXM6MsoTJqLzYeno1C82mWw76OVsE/edit?usp=sharing

As for electrical (5-6 codes appeared there after truck was from the dealer 12 days ago), no codes before
Codes found and cleared:
B1325 Control Module Power Circuit Voltage below Threshold
B127E Front Video Display Output Signal
U0121 Lost communication with Electronic Brake Control Module, Test Failed
U0401 Invalid Data Received from Engine Control Module
U0415 Invaid Data Received From Engine Control Module
Code found not cleared
C0800 Device power #1 (low current#1) circuit malfunction

Seem fine to me. Was that a drive or just idling and raising the rpms in park? Have you checked your grounds and the battery cables? It's common for the trims to be negative, up to -10 or so while idling and then it will attempt to get to zero and if you are driving at a steady speed for a while the computer will get there usually. Sometimes not but close. Depends on fuel, weather, driving habits, etc.

 

[smokey_mountain]

It was driving. I have checked the battery connections all seem to be tight. I thought about disconnecting every connection at the body but I will need to figure out which connections and wires to re-tighten.

Seem fine to me. Was that a drive or just idling and raising the rpms in park? Have you checked your grounds and the battery cables? It's common for the trims to be negative, up to -10 or so while idling and then it will attempt to get to zero and if you are driving at a steady speed for a while the computer will get there usually. Sometimes not but close. Depends on fuel, weather, driving habits, etc.

 

[smokey_mountain]

You are spot on, everyone suggests the cables and/or battery. I have called the local dealer, asked them if they would take the truck in and check it, they said "these codes are common and nothing to worry about" we would clear them for you...

Battery cable(s).

 

[91RS]

It isn’t just connections. The cables have high resistance internally. They are common but are something to worry about because they can cause problems such as just the radio screen going blank up to the engine stalling if they’re bad enough.

 

[smokey_mountain]

Yes, I will not take to that dealer for sure who spoke like that. I have scheduled with a selling dealer, so I expect them to help a bit more. All these codes appeared after selling dealer worked on the truck 12 days ago, they reflashed ECM. Now I wonder what they did.

It isn’t just connections. The cables have high resistance internally. They are common but are something to worry about because they can cause problems such as just the radio screen going blank up to the engine stalling if they’re bad enough.

 

[smokey_mountain]

This is how truck shakes when is fully warm, stopped in D in idle. Running 93 Octane Exxon. Bottle test shows the pattern of shaking if you watch carefully. BTW, if I put Regular gas - shaking pattern is the same except amplitude is wider.