P1175 and P0300

dirtdriver11 · February 27, 2019

I have a 2008 Sierra 1500 with the 6.0l. I keep getting intermittent P1175 and P0300. I have some freeze frame data but I dont fully understand it. Anybody help me out or point me in the right direction. I was leaning towards injectors.

Edited February 27, 2019 by Chris Thornton

dirtdriver11 · February 27, 2019

Not sure why pictures wont show up?

riverbanks · February 27, 2019

Comprimized?same here,error

carnau · February 27, 2019

Your 1175 code is for the Fuel trim on bank 2. I have run into several things causing this on these vehicles. The 300 could also be causing this as well or this could be causing the 300 so lets do some digging.

Do you have a scan tool that shows misfire data? If so, which cylinder/s are showing the skip?

If you look at your bank 2 (right/passenger side) exhaust manifold, do you see any bolt heads missing/broken off? Do you hear an exhaust leak? I have run into multiple vehicles with broken bolts on both banks which can cause this issue.

Another thing is, there is a bulletin about this code - #03-06-04-030H pertaining to the fuel injectors being restricted and causing this issue. It will cause the 300 and the 1175. I am not sure what kind of tool you are using to diag with, but if it has access to a cylinder/injector balance let me know and I will walk you though testing the injector drop.

For these codes, you will really need access to a scan tool that can do some special functions in order for me to help you further. Or, even if the scan tool can give you misfire data I can help you further with that. Without it, it will be loading the parts cannon at it and firing and I don't believe in putting parts on your vehicle it doesn't need.

If you're looking for a inexpensive scanner that will give you misfire readings. This on is on the cheaper scale and will do that. https://amzn.to/2IGugQe

dirtdriver11 · February 28, 2019

3 hours ago, carnau said:

Your 1175 code is for the Fuel trim on bank 2. I have run into several things causing this on these vehicles. The 300 could also be causing this as well or this could be causing the 300 so lets do some digging.

Do you have a scan tool that shows misfire data? If so, which cylinder/s are showing the skip?

If you look at your bank 2 (right/passenger side) exhaust manifold, do you see any bolt heads missing/broken off? Do you hear an exhaust leak? I have run into multiple vehicles with broken bolts on both banks which can cause this issue.

Another thing is, there is a bulletin about this code - #03-06-04-030H pertaining to the fuel injectors being restricted and causing this issue. It will cause the 300 and the 1175. I am not sure what kind of tool you are using to diag with, but if it has access to a cylinder/injector balance let me know and I will walk you though testing the injector drop.

For these codes, you will really need access to a scan tool that can do some special functions in order for me to help you further. Or, even if the scan tool can give you misfire data I can help you further with that. Without it, it will be loading the parts cannon at it and firing and I don't believe in putting parts on your vehicle it doesn't need.

If you're looking for a inexpensive scanner that will give you misfire readings. This on is on the cheaper scale and will do that. https://amzn.to/2IGugQe

This is what I pulled from my scan tool but dont fully understand it. Makes me think of injectors but dont want to throw parts at it for nothing. As far as exhaust, I dont see orhear anything there.

riverbanks · February 28, 2019

Right off the bat,I saw low fuel pressure

carnau · February 28, 2019

15 hours ago, riverbanks said:

Right off the bat,I saw low fuel pressure

I saw that too. The problem with that is though. This is a FPCM truck. The FPCM controls the amount of fuel pressure and 44 can be plenty.

Ignition ON, engine OFF, command the FPCM Fuel Pump ON with a scan tool. Verify the fuel pressure is between 345–690 kPa (50–100 psi) with the pump running.

Engine idling at the normal operating temperature, Verify the FPCM scan tool Fuel Rail Pressure Sensor parameter is between 296–310 kPa (43–45 psi).

So I dont think the fuel pressure is the problem.

Pull the Number 1 plug and the number 7 plug and lets check for oil fouling. That's the first and last plug on the drivers side. Oil fouling can cause the skip and it can also cause the p1175. I actually have a youtube video on how to fix this on these trucks because it is a pretty common problem. That's why I wanted to see the misfire data.

When you have the plugs out look at it from the bottom and see if it has trash (excess oil build up) inside the plug. That a picture of it and post it on here.

riverbanks · February 28, 2019

Right,his data showed at a higher rpm,44,too low?

dirtdriver11 · February 28, 2019

I just replaced the plugs a couple months ago but when iI get a chance I will pull the plugs out and take a couple pictures. FYI the afm was already removed when I bought it and it has 224,00 miles on it if that helps any.

19 hours ago, carnau said:

Your 1175 code is for the Fuel trim on bank 2. I have run into several things causing this on these vehicles. The 300 could also be causing this as well or this could be causing the 300 so lets do some digging.

Do you have a scan tool that shows misfire data? If so, which cylinder/s are showing the skip?

If you look at your bank 2 (right/passenger side) exhaust manifold, do you see any bolt heads missing/broken off? Do you hear an exhaust leak? I have run into multiple vehicles with broken bolts on both banks which can cause this issue.

Another thing is, there is a bulletin about this code - #03-06-04-030H pertaining to the fuel injectors being restricted and causing this issue. It will cause the 300 and the 1175. I am not sure what kind of tool you are using to diag with, but if it has access to a cylinder/injector balance let me know and I will walk you though testing the injector drop.

For these codes, you will really need access to a scan tool that can do some special functions in order for me to help you further. Or, even if the scan tool can give you misfire data I can help you further with that. Without it, it will be loading the parts cannon at it and firing and I don't believe in putting parts on your vehicle it doesn't need.

If you're looking for a inexpensive scanner that will give you misfire readings. This on is on the cheaper scale and will do that. https://amzn.to/2IGugQe

This is what I pulled from my scan tool but dont fully understand it. Makes me think of injectors but dont want to throw parts at it for nothing. As far as exhaust, I dont see orhear anything there.