laminarflow

I have been driving with it in this state for a while. Takes 2-3 days for the code to return. Sometimes the throttle can be a bit mushy/vague which is a symptom of cat issues. The truck is otherwise in immaculate condition; just been an expensive year (new AC condenser, new rad, transmission rebuilt ... now this).

Thanks Cameron. The third cat isn't associated with error codes - correct? From what I've read, it was only added to ensure the vehicle passed emission standards in CA.

I’ve got a 2015 GMC Sierra 1500 (5.3) with 165K KM. Check engine light is on and it’s the catalytic converter. Just got off the phone with GM Parts: quoted $3672 CAD for a new OEM cat -just the part (y-pipe - 3 cats). So that’s not going to happen. This truck has become a money pit in the past 12 months and I need to reign-in the costs. A few questions: 1) Aftermarket cats are about 1/2 the price. Is there a brand you guys recommend … like Magnaflow? 2) When the vehicle throws a code (for cats), typically which cat is it? MagnaFlow also sells the third cat for about $400. 3) Any other options? Thought about deleting the cats altogether, but then I’ll need to get the truck tuned. 4) Aftermarket cats should meet or exceed OEM specs - it won’t keep throwing codes will it? Thanks guys!

"Look for burt or shorted o2 sensor wiring. Cats don't fail like that. And if it was clogged you would now it due to sluggish accel and bogging." Unfortunately, I am getting a sluggish/bogged acceleration. Clogged?

Hey everyone ... I have a 2015 1500 with a V8/5.3. It's got 93,000 miles on it and after rebuilding the transmission at 90K (ugh), I'm now throwing a code for the catalytic converter. What kind of issues (upstream) lead to a catalytic converter failure? I just want to cover all my bases here. Additionally, anyone have any luck 'cleaning' a catalytic converter (if it's clogged) either by fuel additives (skeptical) or physically removing the converter and cleaning it? Thanks guys.

Hey everyone, just looking to get a bit of advice. I have a 2015 Sierra 1500 that I bought new. Now has 148K kms on it (91K miles). 6 spd with 5.3L. Though research on this forum and YouTube I believe the torque converter is on its last legs. This truck hasn't towed or hauled massive loads ever; mostly used to haul camping gear, kids and skis around. So much for professional grade - haha. I plan to drive this thing as long as possible (at least for another 100K kms) any advice regarding further preventative maintenance while the transmission is pulled. I've read that using a 2500 HD TC is a good option - does anybody agree? Anything else I should replace while the mechanics are in there? Thanks everyone!

Just made an appointment to get my AC fixed (2015 Sierra). AC went at 115K KM, I now have 127K KM. Assuming it's the condenser; is there a part number I should request to ensure I get the 're-engineered' condenser? Alternatively, any aftermarket condensers that are much better quality? I don't want this to happen again. Thanks guys.

Just spent $28 on new bulbs to rule that out - not the bulbs. No dice. Any other things I'm missing?

Hey everyone! I have a 2015 Sierra 1500 and the driver's side tail lamps/running lamps are not operational. Looking for ideas as to why. Lots of stuff breaking at 120000 KM ... sigh! Brake lights, turn signals, plate lamps, and reverse lights are ALL operational. I've checked the basic wiring around the lamp. The fuses are fine. The ground is clean and secure. The brake-filaments in the bulbs appear to be intact. No moisture in the lamp housing. Anything I'm missing? Probably! ? Thank you for your help/consideration.

I had Rancho's up front and just replaced them with Bilstein 5100's on the max setting. I found the Rancho's fine, but off road they took a long time to settle (i.e. bouncy). The Bilsteins are definitely stiffer, but in a good way b/c they settle quickly. I'm quite happy with them, I just need to swap-out the back.

I get the same thing ... same behaviour. It's not super loud though.

Sleeper ... your truck looks awesome. What are the specs on your tire/wheel combo. I've never took such an interest in tires/wheels until I owned a truck (2015 GMC Sierra). Trying to wrap my head around all the possible permutations.

I noticed the moisture in my lamps as well. I have a 2015 Sierra with 2400 KMs on it. Always concentrated in front of the LEDs when the temperature dips. I know GMC says this is normal, but it isn't. This is my first domestic vehicle after many years of Japanese and European cars and I have never seen this before. If you don't rid the moisture, pretty soon you'll have algae forming inside. Is that normal? It's like a little greenhouse in there. So, tonight I cracked both lamps and taped a fresh desiccant pack in each assembly. That should take care of it I hope. Thinking that a giant truck would have easily accessible headlamps - boy was I wrong. What a mission. I used to think removing the battery in my Subaru to replace a headlamp was bad. When I read "see your dealer" in the GM user manual with respect to the passenger side headlamp assembly I knew I was in for it. You have to completely remove the air filter. Craziness! Why am I doing this to my 3 week old truck!? Being new to domestic vehicles, I have to say there's so many fiddly things that they just don't get right. Fit and finish in some places is terrible. Like the bank of switches below the HVAC controls - they flop around like wet noodles - who OK's a design like that? Dumb little design errors shouldn't exist on a $60K truck.