ksiesel

I recently experienced a P0452 on my '18 Sierra Crew Cab with 6.5' bed. This fault is for the fuel tank pressure sensor reading a lower than expected voltage. All online research I did led me to believe that one had to either remove the bed or drop the fuel tank to access the FTP sensor. I wanted to share that I was able to lie on my back and reach around the frame and fuel tank (between fender and frame) just rearward of the fuel filler neck. The FTP sensor is on the fuel pump header tank on the top of the fuel tank. I didn't take any pictures, but working by feel alone, it is possible to remove the FTP sensor and even to remove the electrical connector to the Fuel Tank module. In my case, once I removed the FTP sensor, it tested good so I re-installed it and went on to checking other things. This meant I needed access to the vehicle side wiring harness that leads to the FTP sensor. The FTP sensor harness joins with the fuel pump module connector harness about 8" from the FTP sensor connector. Again by feel, I removed the connector lock on the fuel pump module connector and disconnected it's connector. With both of these connectors disconnected, you can reach up between the fuel tank and driveshaft to pull the vehicle side harness down from the top of the tank. In my case, I found a broken signal wire very near the FTP sensor connector. A butt splice repair and re-connecting (again blind) and my issues were solved. I should note that I'm 6'4" with pretty long arms so that certainly helps to be able to reach up and around the tank and frame. IMO, anyone who is pulling the bed or dropping the fuel tank to replace an FTP sensor is wasting their time or getting paid by the hour...... Unfortunately, I did not take any pictures, but I still thought this could be helpful to let others know this sensor can be accessed and replaced without removing anything else. I should also note that I previously owned a GMT900 ('07 Silverado Extended Cab 6.5' bed) that failed the FTP sensor and I used the same process to replace it by feel too. I cannot verify this method works on any other cab/bed configurations.

TCM's contain learned values for shift quality. It's possible the term reprogram is getting used out of context here. It may simply imply that the rebuilder is resetting the values in the adaptive learning tables so it will more quickly be able to adapt to the new hardware.

The pressure will not change with or without the weight of the vehicle on the tire. It will change pretty significantly with temperature though. If you never did a sensor relearn procedure on the truck after replacing tires, you can be sure it is still looking for the sensors in the old wheels. Each sensor has a unique transmitter number and this is what the TPMS module in the truck is looking for. The relearn simply changes this association. You can think of it just like a paired Bluetooth connection.

Just a guess, but are you old tires still nearby your truck when you are at home? I suspect your truck may still be learned to the old sensors in the wheels no longer on the truck. Add to that you haven’t driven far enough yet for the TPMS faults to set for not being able to read the sensor (because it’s still at home and no longer in range). I’ve never heard of a 433 MHz sensor pairing and sending ANY data to a 315 MHz system like your K2xx truck is.

FYI, GM did pair the 5.3 with the 8 speed on some packages - maybe not in 2015 though. I have a 2018 that came from the factory with a 5.3 and an 8 speed trans.

My datalink short was right at the terminating resistor on the drivers side. You should be able to check this datalink circuit by measuring resistance from Can H to Can L with the key off and all harnesses/modules plugged in. There should be a 120 ohm terminator at each end and they are in parallel. A good reading will be around 60 Ohms. I believe you can check it at the DLC under the dash, but I don’t recall what pins.

I had something similar with my truck while it was under warranty. It was the datalink wires shorting together up near the rear tire. The key switch is wired to the BCM and it has to tell the ECM to engage the starter relay via datalink. If those two aren’t talking, it won’t crank. I also had all the dash messages you have along with an outside temp reading of -40 (it was around 60 F then). This theory also aligns with your observation that a scan tool will not connect.

I believe the wheels from 19+ will fit the K2, however the TPMS sensors use a different frequency so you will have to swap them or get new ones that work with the K2.

Sounds like a vacuum pump failure. I’d recommend calling your dealer with the symptoms as I believe GM has a program covering these even beyond the warranty period. I’m sure others will be along to share specifics of that coverage program.

Each sensor has a unique sensor ID. Your truck has a table that these sensor ID's are written into when you do the sensor learn procedure. If you removed the sensors from the vehicle (as they were pulled with the wheels), you will get a TPMS light after you drive enough. Having said that, if you put your old wheels and tires in the bed, your truck will go on reading them and not give any codes or lights. When you perform the TPMS learn procedure, what you are doing is telling the truck which sensor ID to write to memory that each wheel location (LF, RF, RR, LR) in that order.

The dealer may be offering you a bit on the low side for your ‘17. One thing to remember is that you will not be paying tax on the trade in value so if the dealer offers $50k for trade and your sales tax rate is 7%, that would be $3500. If you were to do a private party sale, that’s how much more you’d have to sell it for to break even.

It’s not a T1, but the magnetic ride on my 2018 Denali is impressive. It’s the best riding truck I’ve ever driven.

Search for this "Fernco PQC-102 2" Qwik Cap". Its what I used. You don't need the clamp that comes with it. This works very well.

In the 2018, it’s not really a seat cooler as there is no cooling module in the system. Instead, it’s a ventilation fan so until your cabin temp comes down (from the A/C), all they are doing is pulling hot air through the seat. In terms of flow, they pull the air through the seat and blow it out the back and bottom. There are two fan motors per seat, one for the bottom and one for the back. I have actually been pretty impressed with how much difference the ventilation makes vs just having a standard leather seat.

How difficult was it to get the old one off the valve cover, and did you end up breaking any of the plastic off that you struggled to find among the rockers?

Can you give the part number for this? Also, can you confirm that you didn't need to modify the locking grooves prior to installing?

I see most are doing the cargo on with reverse using a diode, but why couldn’t this one just be done with a piece of wire (no diode)? I think it would then give you Cargo on with Reverse as well as reverse on with cargo. I don’t see where this would be a bad thing and would give more light around the rear of the truck when loading / unloading with the cargo switch too.

For those who want to go back to stock for trade in, why couldn’t you just do this mod as suggested but remove the belt from the vac pump and leave the vac pump installed (cap the vac port as it’ll probably see crankcase pressure with the pump not being driven)? In this way, the vac pump will still have oil flow through it and it won’t be able to flow out the vac port. The pump won’t be turning so it won’t develop any vacuum or take any power from the crank. When you want to go back to stock, just put the belt back on and route the plumbing back to stock.

I thought I read on here that GM extended the injector coverage on the K2xx GDI injectors. I’m sure if you do a search, you’ll find something about it.

Could the reason for turning the fans on when the coolant temp doesn't come up be a fail safe for a failed in range coolant temp sensor? By turning the fans on, you prevent engine overheat in this scenario. Back in the days of a belt driven mechanical fan clutch, this wasn't needed as the fan clutch was reacting to the heat coming off the rad and they were designed to fail full on.

Don't think it will fix the root cause, but should help to avoid low speed accidents by allowing the ABS modulator to kick in sooner and provide more braking with the same pedal force when vacuum is too low. At least that's what I think this recall SW is doing.

I actually hope they do. That's one feature on the truck that I personally have no use for and would be happier if it wasn't there in the first place. Sunroof is the other one, but the truck I found on a lot has that too! BTW, I did have a truck with the heated washer recall. I actually loved that feature and never had that recall done until I was ready to sell the truck.

By reading through enough of the attachments, this recall is going to give you more hydraulic brake boost (not through vacuum) when the mechanical vacuum pump is struggling to keep up, but has not yet under performed enough to show a low vacuum pressure fault. I didn't realize the system had this capability, but seems to me like they are using the ABS solenoids to increase brake boost when the mechanical vacuum pump doesn't have enough boost. The way I read it, this recall does not directly address the cause of the failing vacuum pumps (claimed to be sludge buildup on oil inlet screen), instead it just attempts to keep the stiff pedal situation from sneaking up on drivers and causing an accident.

The condenser is also a transmission cooler. It has two flow circuits in the same component so you’re going to lose a small amount of ATF when you remove the condenser. As to the dipstick, my understanding is that the 6 speed has a dipstick in the K2 trucks, but the 8 speed does not. On the 8 speed, there is a stand pipe on the plug in the pan and you fill through that pipe, but only after the fluid is up to temp and with the engine running on a level surface.

[email protected] BTW, I did try sending them another request after my first and second rejected attempts. Maybe they've changed their policy as they promptly responded with the build sheet on the third try.