What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

FIXED * 2014 Silverado 5.3 High Country DIES while driving

ZombieK5

ZombieK5

1/2 ton status
 Premium
Joined
Feb 21, 2020
Posts
1,167
Reaction score
1,069
Location
Bucks County, PA
History:

2014 Silverado 5.3 purchased 18 months ago.
Late Summer of 2025 I performed major rust abatement surgery and replaced MOST of the rear frame.
During the frame repair I replaced the fuel pump with a Delphi unit.
Before the frame repair, the truck ran fine with no engine issues, sometimes a slow start in the morning.
After the frame repair the truck ran fine but I started getting code:

P018B - Fuel Pressure Performance

This code would come and go with no changes in engine performance. During the frame repair I replaced the fuel pressure sensor with a NEW GM Original sensor. The engine was reading mostly 43-50psi. That may be a little low. The HPFP was working in normal parameters. Nothing bad happened for the past 5 months and no new or unusual codes. Normally the truck would not even register the P018B code, I would just see with with my scan computer. Every now and them it would cause a CEL and I would read the codes and clear them...no problems.

Two night ago the truck DIED at a local gas station while it was running. I used my bi-directional scan computer and was able to read codes and there were NO CODES. The truck would not start. Sounded like it was starved for gas. I would half ass try to start and run/bog down at about 200rpm the die. I kept trying to start to no avail.

After about 30 min I used the scan tool to prime the fuel pump. Did this about 5 times. The truck started and ran NORMAL. Cancelled AAA and drove it home. I then got the P018B code and went ahead and swapped out the fuel pressure sensor for another NEW one. Truck started and ran NO issues. However, during this time I also got code:

P2635 - Fuel Pump Flow Performance

This code has several factors that influence it including the fuel pump itself however I am able to run the fuel pump with my computer. The fuel pressure sensor is new. BUT another factor is the Fuel Pump Control Module (FPCM). It is the flat silver box above the spare tire. This could be the issue. I don't think it is the fuel pump. It runs whenever I turn it on with the computer. It also runs with the key on.

Tonight it did it again. However it would not start when I primed it. I waited 30-40 min and then it started. This is telling me electrical and therefor the FPCM

See attached video for what it was doing when we tried to start it.

Question:

RockAuto has the FPCM for about $80 which I am sure is cheaper than the dealer. It is also the GM Genuine FPCM. It needs to be programmed.

Will a dealer program the unit if I simply bring it in and give them the vehicle VIN info?? Or will I have to buy the unit from them and pay their price??

Another question, HOW MANY fuel rail pressure sensors does this truck have: 5.3 L V*?

My scan tool is getting reading from two fuel rail pressure sensor BUT the GM Shop Manual only shows one. On my computer it is reading:

FUEL RAIL PRESSURE SENSOR 1 58.016 psi and 0.57 Volts
FUEL RAIL PRESSURE SENSOR 2 72.52 PSI and 4.43 Volts

Are these normally 5V sensors? IF There is a 2nd fuel rail pressure sensor, WHERE IS IT?? The reading at 0.57 Volts seems too low.

Thanks for any help

View attachment 20260322_204108.mp4

20260322_204058.jpg
 
Last edited:
You could try the original pump again. Has the filter been changed? It's possible that these pressure codes only log when the engine is running. Is it possible it's mislabeling the tank pressure sensor as a fuel rail one?
 
Blue85 said:
You could try the original pump again. Has the filter been changed? It's possible that these pressure codes only log when the engine is running. Is it possible it's mislabeling the tank pressure sensor as a fuel rail one?
Click to expand...
Old pump is gone. The tubes were basically dust. New filter and new fuel lines from fuel filter back to tank

The fuel rail sensor readings are not the fuel pressure sensor readings. It is a separate category.
 
My thought is that module you mentioned. Don't know if you ever watch SMA on youtube, but he has said before with where those modules are located they tend to go bad. With your rust history I would jump to that as well.
 
EvilGenius said:
My thought is that module you mentioned. Don't know if you ever watch SMA on youtube, but he has said before with where those modules are located they tend to go bad. With your rust history I would jump to that as well.
Click to expand...
Yea, I've watched those videos and I've learned on my own that the engineers at General Motors are idiots. Every car I own except for the 2014 Silverado has the ABS brake pump and module located in the engine bay so it stays relatively dry. Not General Motors, "Let's put that bad boy underneath the driver's seat on the frame rail so it gets good and soaked every time they drive in the rain." Then they said, "here hold my beer, let's put the Fuel Pump Control Module above the spare tire near the rear tires so this absolutely necessary piece of electronics gets good and soaked. AND let's make it programmable so they have to come into the dealership to get it worked on."

Not happy
 
The design intent isn't to maximize lifetime of components. It's to minimize assembly labor, while making it through the warranty period. And rain...try blasting everything in salt brine for hundreds of thousands of miles.
 
I’m leaning towards the fpcm but to tie back to the frame repair last year I would double check the grounds back there for the module and the pump.

Main reason being you can toss a new module in and the ground is loose you will be going to buy another one. As a bad ground will wreak havoc on modules. A loose ground also plays into the intermittent nature of the problem.

As far as programming goes I hate to say it, but no dealer is typically set up to program any modules outside of the vehicle. They have to be plugged into the truck and the program is pushed through the same connector you plug your scan tool into. There is another issue too. Dealers are going to be pretty apprehensive to 1. Install parts you bring in and 2. Proceed without doing their own diag. I point that out even if they have you sign off that if it don’t fix your problem you still pay for the time spent programming. Unfortunately most have been burned doings favor to just do the programming and then get called out because the truck don’t run. Not to mention the fact most won’t install parts you haven’t bought from them.

I know it’s probably what you don’t want to hear but that’s the reality. It’s crappy and I don’t agree with the concept of a DIY guy not being able to fix his own truck. Then I look at my time at a dealer and understand why they don’t like installing outside parts. Besides the obvious fact they didn’t get to make any money on the part, they can’t validate anything about it. Lots of counterfeit parts or just substandard parts that may not work right. I’d allow it despite my parts manager bitching about it, but it was made crystal clear. We would get paid the time to program the part regardless if it worked or not. If it did great. If it didn’t then I’d give the customer the option for my guy to diagnose. We would not proceed until we got the green light.

If you have a buddy at a local GM dealer you might have a fighting chance.
 
Didn't you POR-15 the whole frame back there? How was the ground point prepped?
ZombieK5 said:
Old pump is gone. The tubes were basically dust. New filter and new fuel lines from fuel filter back to tank
Click to expand...
Usually, the pump can be separated from the sending unit and if it ran, that's a valid spare for the trail or troubleshooting (or for one of your kids broken cars :haha:)
 
Blue85 said:
Didn't you POR-15 the whole frame back there? How was the ground point prepped?

Usually, the pump can be separated from the sending unit and if it ran, that's a valid spare for the trail or troubleshooting (or for one of your kids broken cars :haha:)
Click to expand...
I didn't POR15 but I did paint. I made sure the grounds were to bare metal the I Fluid Film'd over the grind wire/bolts
 
ZooMad75 said:
I’m leaning towards the fpcm but to tie back to the frame repair last year I would double check the grounds back there for the module and the pump.

Main reason being you can toss a new module in and the ground is loose you will be going to buy another one. As a bad ground will wreak havoc on modules. A loose ground also plays into the intermittent nature of the problem.

As far as programming goes I hate to say it, but no dealer is typically set up to program any modules outside of the vehicle. They have to be plugged into the truck and the program is pushed through the same connector you plug your scan tool into. There is another issue too. Dealers are going to be pretty apprehensive to 1. Install parts you bring in and 2. Proceed without doing their own diag. I point that out even if they have you sign off that if it don’t fix your problem you still pay for the time spent programming. Unfortunately most have been burned doings favor to just do the programming and then get called out because the truck don’t run. Not to mention the fact most won’t install parts you haven’t bought from them.

I know it’s probably what you don’t want to hear but that’s the reality. It’s crappy and I don’t agree with the concept of a DIY guy not being able to fix his own truck. Then I look at my time at a dealer and understand why they don’t like installing outside parts. Besides the obvious fact they didn’t get to make any money on the part, they can’t validate anything about it. Lots of counterfeit parts or just substandard parts that may not work right. I’d allow it despite my parts manager bitching about it, but it was made crystal clear. We would get paid the time to program the part regardless if it worked or not. If it did great. If it didn’t then I’d give the customer the option for my guy to diagnose. We would not proceed until we got the green light.

If you have a buddy at a local GM dealer you might have a fighting chance.
Click to expand...

Yea, I'm a little pissed they are making cars that people can't fix. I won't ever buy a new car. I may lease a new car for my wife so we can dump it before warranty runs out.

I have the module on the way. One dealer checked the procedure and he said it didn't need to be programmed. If it needs programming it will be $199. Ughhhh. Fingers crossed.
 
You could play around with trying to program it yourself. It's not rocket science if knucklehead mechanics can do it everyday. It's not hidden behind inaccessible tools either. Here is a reddit thread about doing some programming.

However I think if it's only $200 from the dealer that's cheaper than playing around with the subscriptions from GM. My looking showed you would need the SW and then the vehicle license. Similar to how hptuners works with needing credits.
 
EvilGenius said:
You could play around with trying to program it yourself. It's not rocket science if knucklehead mechanics can do it everyday. It's not hidden behind inaccessible tools either. Here is a reddit thread about doing some programming.

However I think if it's only $200 from the dealer that's cheaper than playing around with the subscriptions from GM. My looking showed you would need the SW and then the vehicle license. Similar to how hptuners works with needing credits.
Click to expand...
GM does make it accessible for independent shops for sure. But the subscription is not cheap. For a shop working some volume it would be a worthwhile investment. On an individual basis, not so much.

@ZombieK5 :

When I get to my hotel tonight I’ll pull up the fuel pump module replacement procedure in SI to know for sure if programming is required or not.
 
ZooMad75 said:
GM does make it accessible for independent shops for sure. But the subscription is not cheap. For a shop working some volume it would be a worthwhile investment. On an individual basis, not so much.

@ZombieK5 :

When I get to my hotel tonight I’ll pull up the fuel pump module replacement procedure in SI to know for sure if programming is required or not.
Click to expand...
Just removed the old unit... Outside is crusty but no green meanies inside the plug.

20260325_163425.jpg

20260325_164350.jpg

20260325_164355.jpg

20260325_164346.jpg

20260325_164540.jpg
 
ZooMad75 said:
When I get to my hotel tonight I’ll pull up the fuel pump module replacement procedure in SI to know for sure if programming is required or not.
Click to expand...
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.
 
I’m pretty sure that module needs to be flashed. Has to be zapped with the vin and firmware.
 
You must log in or register to reply here.

Latest Posts

Top Bottom