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FIXED * 2014 Silverado 5.3 High Country DIES while driving

ZombieK5 said:
How do I put it into SERVICE MODE?

Also, Cylinder Deactivation Exhaust Control Valve Learn sounds almost as bad...???
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Service mode doesn't exist for these trucks. I believe it is specific to vehicles without keys, aka push button start vehicles.

The Cylinder Deactivation Control Valve Learn doesn't apply to this either from what I can tell. Not as confident in which vehicles it does apply to, but I don't believe it is this one. The cylinder deactivation technology in these engines is "dumb" in that there isn't a feedback mechanism that knows if the exhaust lifters are collapsed. The solenoids just redirect oil pressure to collapse the lifter. There is no sensor to dictate anything, which means there isn't a "learn" associated with the cylinder deactivation on these engines. Or at least that's what makes sense to me. I attempted to search through the service manual to find anything indicating this learn procedure applied and didn't see anything to that effect.

This procedure is the same across a bunch of vehicles from what I can tell. The service manuals are "live" docs of a sort these days and I think they got too smart. This doesn't appear to apply to these trucks at all from what I can tell. So my thoughts are you can just plug in the new module and be good to go. I did look up an old SMA video and he replaced one of these in a similar year range colorado/canyon and it didn't appear he did any sort of programming.

Good luck!
 
EvilGenius said:
Service mode doesn't exist for these trucks. I believe it is specific to vehicles without keys, aka push button start vehicles.

The Cylinder Deactivation Control Valve Learn doesn't apply to this either from what I can tell. Not as confident in which vehicles it does apply to, but I don't believe it is this one. The cylinder deactivation technology in these engines is "dumb" in that there isn't a feedback mechanism that knows if the exhaust lifters are collapsed. The solenoids just redirect oil pressure to collapse the lifter. There is no sensor to dictate anything, which means there isn't a "learn" associated with the cylinder deactivation on these engines. Or at least that's what makes sense to me. I attempted to search through the service manual to find anything indicating this learn procedure applied and didn't see anything to that effect.

This procedure is the same across a bunch of vehicles from what I can tell. The service manuals are "live" docs of a sort these days and I think they got too smart. This doesn't appear to apply to these trucks at all from what I can tell. So my thoughts are you can just plug in the new module and be good to go. I did look up an old SMA video and he replaced one of these in a similar year range colorado/canyon and it didn't appear he did any sort of programming.

Good luck!
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VERY Interesting. I would love to see that SMA episode. LOVE that guy!
 
Good news bad news. I got the module installed and the truck started like up as if it was brand new. However, as soon as I hooked up the computer it started throwing the p2635 code again. No drivability issues. The car drove and felt normal. I have my stepson out driving it right now to see if it will replicate the issue and stall. He says the issue has never happened while driving at speed. He says it is only happened, on two different occasions, after he starts the car puts it in gear and rolls a little bit forward. The car would sputter and die and then it won't start again for about 45 minutes. We've had the P2635 code pretty much since we've had the truck and it's only recently that it has done the stalling and not starting routine. As mentioned before it has a new Delphi pump in it. I've attached two videos that I took today while driving it. The first one is while the engine is idling at low speed and rolling forward at low speed. The last one is at higher speed driving down the road. These are the fuel trims. The fuel pump pressure does look a little higher than it did before this issue started with the old control module.

Sorry the videos are a little jumpy but I was driving while holding my cell phone camera. You can pause the video to get a reading. Now that I look at the video the fuel pump still seems to be a little bit low.

View attachment 20260327_153933.mp4

View attachment 20260327_154134.mp4
 
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Isn't it possible that the code and stalling are unrelated?
 
Blue85 said:
Isn't it possible that the code and stalling are unrelated?
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Anything with modern vehicles is possible. I've I've been reading about people with similar problems and the solution somehow involved the automatic radiator shutters. Who the hell knows.

Regardless I firmly believe the problem is electrical. When the truck shut down and would not start it sounded like it was not getting any fuel. Almost as if I had ran it out of fuel. However, during the time it would not start using the key, I was able to use my bi-directional scan computer and the fuel pump function normally. I could get it to run every time. The fuel pump would also run when I turn the key on but did not try to start the engine.

Then magically after waiting about 45 minutes the truck starts again with no issues.

In the late 1980s I had a similar problem with my 280zx. After running the car in Texas hear I would get to a destination and park. If I came out within 30 minutes the car would not start. I would have to wait at least 45 minutes to an hour for it to cool down before it started. A long story short, the issue was the ignition control module bolted to the side of the distributor. When it got hot it would not work until it cooled down. Nissan's test procedures involve using a heat gun to warm it up in the service bay and see if the car would start.

Both times my truck stalled, it took about 45 minutes until it was start again. That tells me it is electrical in my experience. I don't think it was fuel pressure related. The fuel pressure in that particular truck bleeds off pretty quickly after you turn it off. While I had the fuel pump control module out of the truck I jumped the power and ground wires in the pigtail connector. When I did that the fuel pump work instantly. That's telling me that the fuel pump is probably not the issue. I've never really come across a fuel pump that did something like this. Fuel pumps gradually lose functionality over many many years. Fuel pumps also don't necessarily get hot inside the gas tank since they are kept cool by the gas it is immersed in.

The only other electrical device in the fuel system, besides the ECU, is the fuel rail pressure sensor and that seems to be working fine.

If this happens again it looks like I will be replacing the fuel pump, which as I've mentioned many times before is brand new, with a General Motors genuine fuel pump which is $285 on rockauto.

It sounds like I am using the parts cannon on this but the diagnostic equipment I have has reached its limit.
 
ZombieK5 said:
I've been reading about people with similar problems and the solution somehow involved the automatic radiator shutters. Who the hell knows.
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I have some experience with this. I had a Cruze "eco" with the radiator shutters. Since the eco had a different FPCM than the regular one, they added the shutter control to it. When the shutters would freeze, the PCM reported a fuel pump fault code. That could have led to frustration! My daughter's current car took a front end hit and whoever repaired it didn't bother to install the shutters or actuator, so now it has a permanent check engine light. A decent scan tool does report it out as a louver error, but a cheap one would have you swapping FPCM or fuel pumps.

Your problem almost sounds like a security thing. When it won't start, have you tried disconnecting the battery? Maybe something is resetting in that 45 minutes.
 
Blue85 said:
I have some experience with this. I had a Cruze "eco" with the radiator shutters. Since the eco had a different FPCM than the regular one, they added the shutter control to it. When the shutters would freeze, the PCM reported a fuel pump fault code. That could have led to frustration! My daughter's current car took a front end hit and whoever repaired it didn't bother to install the shutters or actuator, so now it has a permanent check engine light. A decent scan tool does report it out as a louver error, but a cheap one would have you swapping FPCM or fuel pumps.

Your problem almost sounds like a security thing. When it won't start, have you tried disconnecting the battery? Maybe something is resetting in that 45 minutes.
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Haven't tried the battery disconnect.

I am using a Murcar bidirectional scanner. it it pretty does everything but doesn't have all the bells and whistles as a Snap On or Alltel computer. I can see the louver module and no errors. Issue only happens when the truck is well warmed up so louvers should be open.
 
ZombieK5 said:
Any word on the module needing programming? I just got notification from RockAuto that the part came in today. I'm going to try and put it on tonight.
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Sorry dude, completely lost track. Damn squirrels!

But zero need for programming. Procedure is simple remove/replace. Plug and play.
 
ZooMad75 said:
Sorry dude, completely lost track. Damn squirrels!

But zero need for programming. Procedure is simple remove/replace. Plug and play.
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I already installed it and the truck starts and runs fine. I still ran into the p2635 code again but there doesn't appear to be any bad behavior yet. I need my stepson to drive the truck around a lot more today.
 
OK, we have not had alot of time to drive and test the new FPCM but so far so good. We have noticed extended crank times in the morning. Seems the truck is getting no fuel. Starts every time after about 10 seconds of cranking.

Once we get it back from getting aligned, we put a 3" leveling kit on it this week, we will see what happens.

Any thoughts on why it cranks for so long in the mornings??
 
That sounds almost like a leak in the high pressure fuel system. It should retain pressure through key cycles. How long of an interval are you talking between starts?
 
EvilGenius said:
That sounds almost like a leak in the high pressure fuel system. It should retain pressure through key cycles. How long of an interval are you talking between starts?
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That's the thing, it's unpredictable. If it happens, it happens in the the morning. There is no gasoline smell and the HPFP readings are where they should be.
 
I installed a brand new General Motors OEM fuel pump and it appears to have completely fixed the problem. My disappointment with Delphi fuel pumps cannot be measured. I had to get five people to help me pull the truck bed off so I can swap out the fuel pump and then put the bed back on. Having those people remove the bed for me made all the difference. Turn out to be a 45 minute job versus a couple hour job if I drop the fuel tank or just tilted the bed upwards. The problem has been fixed for 2 weeks and so far no engine codes and the engine is not died.
 
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