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By Andrew Selinger
I have 2021 AT4 with the 6.2L, just recently a check engine light has come on and am a bit stumped on it. I have read the codes on the ODB11 and the reader I have shows a P2CB9 code but it give me an "information unknown" reading. My GMC app however tells me that nothing is wrong and all systems are normal.
I search online and find that the P2CB9 code is a "cooling fan 2 underspeed" however I live in Canada, its -25 degrees Celsius outside and there should be no reason that cooling fan 2 needs to run, or if I need to get it to run, its too cold out to try and get it to engage.
Would taking the negative battery post off reset this code? its not like its immediately urgent in my life to get it to the dealership due to im not worried about it overheating, but its blocking my command start from working and its pissing me off because its cold outside.
Am I chasing the right rabbit?
Thanks in advance
Hello Everyone! Before I get started I want to thank anyone in advanced who responds with pertinent information.
I'm looking for a replacement exhaust system for my 09 Silverado 6.2L 4x4 Crew Cab/Short Bed. My current system has lots of rust (living in MD, they heavily salt & brine the roads here) and has sprung an exhaust leak right behind the muffler on one of the pipes.
I've been searching around (thought it would be easy to find a system) but have not had luck in finding what I have been searching for. There are plenty of systems for 5.3L & 6.0L motors but scant any for 6.2L.
On my truck currently is an aftermarket cat back system that was there when I bought the truck (not sure which brand.) It is a single in / dual out muffler with dual pipes going out the bumper.
What is the factory flange diameter at the end of the factory Y pipe? I'm seeing conflicting information (this will help me determine what muffler to buy if I piece meal a system together)
If you have any suggested systems, here's what I'm looking for
Material: 304L Stainless Steel
Configuration: Dual exit at rear bumper
I'd consider a long tube header setup w/ high flow cats as well (I would like to maintain all emissions equipment) any suggestions there are also welcome.
I can always get a quote from a shop but I wanted to shop around first before I did that.
Hello everyone. My first time here. I have a 2021 Sierra AT4 with the 6.2L. I have started to notice a noise when towing our boat that weighs about 6,000lbs. Several times during the trip to and from the lake I hear a rumbling sound that last like 2-4 sec. almost sounds like it can be a jake brake or hitting rumble strips on road. I hit no strips. I can’t recall if it happens on downshift or what. But it does concern me. I drove home from work today with our towing and put it in tow haul mode. It made the noise 3 times in 45 min drive. Any ideas what I’m dealing with? Would it be a bad clutch issue or is this normal? I do have the performance GM installed exhaust and performance GM installed air intake. I called dealer today and they said bring it by and they MIGHT have time to get to it next week. I planned to hit the lake this weekend for Labor Day. Thanks.
I dropped the truck of at the dealer this afternoon to have the Whipple installed. They claim it will take 11 hours, so I should have it back on Friday.
I installed a Borla True Dual S Type cat-back exhaust with the optional resonators to bring the volume down a bit. It really sounds good!
I ordered a new ECM from RockAuto for $200 and sent that to HP Tuners to be modified.
The Whipple took less than a month to be delivered, so I was a caught off guard when I got the shipping notification and “had to” (read: wanted to) rush to get everything set up for the install.
I want to maintain the good relationship with the dealer I bought the truck from, in hopes that, if there are any warranty issues with the truck that could be questionably related, they will work with me. That, and they have been good to me on the other mods I have had done. It also has the Trail Boss lift with an extra inch to level the front, new wheels with 35X11.50R20 Ridge Grapplers and it has Road Armor Stealth bumpers on the front and rear.
I am excited for the the outcome!
We have a 2016 Yukon 6.2L which developed a rattle at approximately 60k miles. Initially I believed the source of the rattle was a heat shield, but everything seems to be tight. It has been to the dealer twice and no progress has been made to resolve the issue. The first time they dismissed the problem and called it "normal" and the second time they believe it's a broken baffle weld in the muffler. What do you think? Thanks in advance
Video with several angles from under the vehicle demonstrating the issue. The problem only surfaces when the vehicle inters v4 mode. Also, the rattle is so loud it is picked up by the Knock Sensors and it pulling timing. Scan performed with HP Tuners VCM Scanner.
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