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2015 GMC 3500HD 6.0l gas
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Discussion Starter · #1 ·
Hello I'm new on here, I hope yall can help me out. I have a 2015 GMC 3500HD 6.0l gas. I recently bought it and then noticed that when in idle it began to run rough and I can give it some gas and at times it will go but very slowly and sluggish then it will pop and start running better or it will shut off at times. I was thinking it was the cats and when I took it to shop,I had them do a complete scan and they found PIP5644 with four o2 sensors bulletin. It just acts weird, I cleaned all ground wires,used a can of seafoam on intake and one in fuel tank, changed all spark plugs and O2 sensor bank 2 sensor 2 since that was the only fault I had at first. I can't seem to find any air leaks but I did noticed that when purging valve comes on truck runs a lil rough and also noticed lights dimming down at the same time. I checked all battery cables and found them to be loose, so I tighten them and also checked purging valve and seems to be working fine, I'm completely lost on this one any taught or advice I would really appreciate it.
 

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These scenarios can be difficult to diagnose. Have you checked fuel pressure/fuel delivery? Your symptoms remind me of symptoms I have experienced when my fuel pump was going out. The diagnostic step that pointed me to the fuel system was putting a fuel pressure gauge on it and seeing that the fuel pressure was low whenever it was running rough/stumbling and high when it was running normally. I'm not as familiar with your 2015 fuel system, but I expect it still has a pump in the tank and that the fuel system still operates under pressure, so I would check the manuals and see how one should test the fuel delivery system.
 
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Discussion Starter · #3 ·
I haven't checked the fuel pressure yet. As I mentioned I noticed it runs rough when the purge solenoid kicks in, it's right by the intake on driver side. I've traced all the evap lines and found no leak, there is another valve next to the tank that has one hose going to the canister and the other is just a vent, whilst I had truck running and running rough,I never felt that valve turn on or do anything. You think that might be an issue, I couldn't unplug the bugger, so I will try again to remove it.
 

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@Malingos , the code you provided is not familiar to me, did you make a typing error?

Did the 6 liter get upgraded to direct injection like the 5.3?
If it did, it will have 2 fuel pumps with injector pressures very high like a diesel.
 

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Discussion Starter · #5 ·
@Malingos , the code you provided is not familiar to me, did you make a typing error?

Did the 6 liter get upgraded to direct injection like the 5.3?
If it did, it will have 2 fuel pumps with injector pressures very high like a diesel.
Hey Raymond, no that is not a fault code that is a bulletin # I was given by a shop but I think they are mistaken, because it says that it's for E92 with codes for all four O2 sensors but mine is an E78 . The truck is gas and it does have two gas tanks, I have no fuel pump codes only codes I get is for O2 sensors and random missfire. All plugs are brand new and I've changed both O2 sensors on bank 2. I just picked up a fuel pressure gauge so I will check it tonight and post results. The ecm I have is a E78 and it seems that it's Gen IV from what I read but if anyone is able to correct me,please do.
 

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Discussion Starter · #6 ·
So I have checked fuel pressure and key on engine off is at around 49psi and in less then 2minutes it dropped to 42psi. Started engine and at idle it was steady at 60psi then withing a few minutes truck began to act up and fuel pressure just bounced back and forth 58 to 60psi and a sudden drop to 55psi. At 2000 or 3000rpms it's steady at 60psi. Only acts up when in idle. Do yall think it's the fuel pump? The truck does have two separate fuel tanks and when I got underneath, well its kinda hard to be 100% but it does sound like the front fuel pump is working harder than the rear one,is that normal?
 

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The rear pump is probably just a tank transfer pump.
The fuel pressure seems low to me; but we need one of the pump guys to tell us for sure.
 

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Discussion Starter · #8 ·
So I have checked the throttle sensor TPS, and didn't find any breaks or damaged wires at connector, but either the TPS is going bad or the ECM signal is intermittent, well that's my guess. I DO NOT have any codes for TPS, fuel pump,EVAP, specific plug or coil. Just keep getting codes for either bank 2 sensor 1 or bank 2 sensor, or all four O2 sensors and random missfire. It is intermittent, happens only during idle or at very slow rpms like at take off, light comes on at time and sometimes it doesn't. Could it be related to the ECM, I have checked and cleaned l grounds... I'm lost guys, if anyone has any further taught I greatly appreciate it. I might end up having the dealer look at it and I'm sure they'll want an Arm and a leg .
 

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the truck has a fuel supply electronic controller .. so put on a scan tool that will read the fuel pressure . see if your truck has direct fuel injection on the 6L .. go to a auto part store call them up auto zone advance auto and most have the scan tool that can read the fuel pressure and also read diagnostic readings .. then post on here what is the problem on the scan tool readings..
a 2015 GM truck does not have ground failures .. but many have injector / fuel pump control electronic device failures . look up the electronic fuel pump controller.
 

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Discussion Starter · #11 ·
2014-2020 GM Fuel Pump Driver Module 23382215 | GMPartsDirect.com ...
many have had the pins on the fuel control module , corrode .. GM fabricated these electrical components in the CCP .... stall rough idle speed drop ..intermittent .
I will look for it and check it out. Would that also cause a voltage drop, I just went for a drive and notice the gauge to be steady past 14 volts, but when it starts to act up it will stay steady at 14 and slight drop and lights would dimmed down as if the alternator was going bad.
 

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Discussion Starter · #12 ·
Well I went to auto zone and oreilly and both where not being cooperative, they say they can not check fuel pressure with scan tool, so only faults are for the O2 sensors and random missfire. I checked the wiring on the TPS and went back about 5inches and found no break, also checked connector at fuel control module and no corrosion one pin seem to be a little spread out so I just close it for better connection but still have same issues. Does anyone know how to properly test or ohm out the TPS? I only show 1.6ohms between pin A & pin B, all other pins just show OL, so I just want to be sure I'm testing it correctly before running to buy one.
 

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Well I went to auto zone and oreilly and both where not being cooperative, they say they can not check fuel pressure with scan tool, so only faults are for the O2 sensors and random missfire. I checked the wiring on the TPS and went back about 5inches and found no break, also checked connector at fuel control module and no corrosion one pin seem to be a little spread out so I just close it for better connection but still have same issues. Does anyone know how to properly test or ohm out the TPS? I only show 1.6ohms between pin A & pin B, all other pins just show OL, so I just want to be sure I'm testing it correctly before running to buy one.
one pin on the connector could have over heated then not a good pin tightly. some had to replace the connector to the control module.
GM has on trucks a alternator on/off program . this is a software that increases MPG ..
the voltage changes and if you have no dash failure lights then that is not an issue. some had to replace the current module next to the battery if the dash light batt is on or the alternator .
O2 sensors do not cause miss fires . TPS has a failure then the PCM will reduce speed to 20MPH .. shutdown the engine then turn it back on then the issue is gone for a little bit of time then does the same issue.
miss fires with new GM trucks have fuel control issues most all the time..
 

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Discussion Starter · #14 ·
I will check wiring further back on connector, any way to ohm or check module of the truck?
 

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Discussion Starter · #16 ·
I puchased this actron code / diagnostic reader AutoScanner Plus CodeConnect - ABS & Airbag Coverage | Diagnostics ....
I plugged this in on my friends truck 2015 GM .. I read the fuel pressure .
see if the auto part store has this cp9680 reader then see how it works. need to put on a credit card to hold the tool ..
Well I will swing by and check it out. I did call Chevy house and they apparently say that it does not have a fuel control module that it has brake control module and body control module right in front of the rear tank. They don't see any bulletins nor any recalls to any issues. Where exactly do you say the fuel module is located at cuz all I found is those two, so am I looking at the wrong one or dealer not sure of what they have?
 

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Well I will swing by and check it out. I did call Chevy house and they apparently say that it does not have a fuel control module that it has brake control module and body control module right in front of the rear tank. They don't see any bulletins nor any recalls to any issues. Where exactly do you say the fuel module is located at cuz all I found is those two, so am I looking at the wrong one or dealer not sure of what they have?
looks like the part # fits your truck ...

2015 Chevrolet Silverado 3500 HDHigh Country, LT, LTZ, WT6.0L V8 - CNG, 6.0L V8 - Flex, 6.0L V8 - Gas, 6.6L V8 - Diesel
Fuel Pump Driver Module - GM (23382215)
look it up then see the module next to the tank on internet the picture is on the part site.
 

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Discussion Starter · #18 ·
I did look it up and according to dealer it says that it's not applicable to my truck VIN #1GD421CG7FF177799 . I have gone back and forth with two dealers and both said that is not a fuel pump module and no recalls or bulletins show up. Last thing they see was one that was done for front fuel tank inspection and recalibration but couldn't give me any further info since GM system was down. #23114650 is the part number on that module thats on my truck and it was superceded but I forgot where I wrote it down. When I was checking wires on that module, I did start the truck to see if I could wiggle the harness but it still acted the same, but I did noticed a strong exhaust smell and some raw fuel, so then I'm thinking if the cat is actually clogged and causing all this issues. That first shop I took it to, was to replace the cat but he had talked me into scanning and then came up with all this chasing around. I might have to get a second opinion from different shop. What ya think?
 

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I did look it up and according to dealer it says that it's not applicable to my truck VIN #1GD421CG7FF177799 . I have gone back and forth with two dealers and both said that is not a fuel pump module and no recalls or bulletins show up. Last thing they see was one that was done for front fuel tank inspection and recalibration but couldn't give me any further info since GM system was down. #23114650 is the part number on that module thats on my truck and it was superceded but I forgot where I wrote it down. When I was checking wires on that module, I did start the truck to see if I could wiggle the harness but it still acted the same, but I did noticed a strong exhaust smell and some raw fuel, so then I'm thinking if the cat is actually clogged and causing all this issues. That first shop I took it to, was to replace the cat but he had talked me into scanning and then came up with all this chasing around. I might have to get a second opinion from different shop. What ya think?
yes bring to another repair shop but do not say that you brought it to another shop.. see if its the same response on the failure.
now you say fuel raw out the exhaust well that can be the direct injector failures...converters will melt down with raw gas in the exhaust ..
 

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Discussion Starter · #20 · (Edited)
Ok well this is what I got so far, got a scanner and cleared all faults and test drove it and it still shows P013D, P2272.

Faults show to be permanent, since both banks sensors are close to each other ,I decided to perform a test and not sure if I'm correct but this is what I did... I switched plugs to opposite O2sensors, and I figured it would pick it up and switch to other bank but it didn't. So is my issue in the ECM or is that normal??? I didn't find any damage to harness, I even peeled back the tape and still nothing.
 
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