08 LTZ bout has me whooped - P069E, P025A and P0230

[AlonzoA]

Hey guys, I've used this form since I bought my Avalanche, and it's helped me a ton. But I hit a wall, so I made an account and gotta ask for help.
I bought this truck a year ago for a great price, but the kicker was that it had 37 CEL codes. Other than that a rust free body and spot less interior so I jumped on it believing I could save this truck. These last there codes I can't get them figured out though. The truck will rough idle and jerk/studder under acceleration or going uphill when these codes are present. And recently I drove over a decent bump in the road and the truck shut off on me, only my dash was still lit up. Luckily I could roll into a parking lot and tow the truck home.
I've changed out the FSCM, fuel pump, fuel pressure sensor that's on top of the block, cleaned the two chassis grounds under the right side, replace upstream o2 sensor on bank 1, replaced plugs and wires, cleaned MAF sensor and throttle body, and inspected the wiring harness to the fuel pump for breaks.
And those codes still show up.
I haven't messed with the fuse block yet I don't know enough about them, but heard they could be a problem. But my block is different than the others I've seen, some of the wiring harness are hard wired to the bottom.
Any ideas?

 

[EXT4ME]

Welcome AlonzoA.

Looks like you have addressed a lot of things dealing with the fuel system.

Perhaps if may be time to let a dealer put their scanner on the thing and try to narrow down the issue.

Sorry you are having all of this trouble.

 

[AlonzoA]

I took it to the local Chevy dealer... Said I need a new engine, nothing more.

 

[ygmn]

Ah why do you need new engine?

What is broken inside?

 

[EXT4ME]

I took it to the local Chevy dealer... Said I need a new engine, nothing more.

Try another GM dealer.

Any brand will do.

Or, you could just give up and ditch the truck for something else.

Sometimes that is the better choice.

I know I have my limits and I'm sure you do, as well.

Life is too short.

Best of luck with your repairs.

 

[AlonzoA]

Ah why do you need new engine?

What is broken inside?

Try another GM dealer.

Any brand will do.

Or, you could just give up and ditch the truck for something else.

Sometimes that is the better choice.

I know I have my limits and I'm sure you do, as well.

Life is too short.

Best of luck with your repairs.

They said I have cam failure (there is light lifter tick that I already but at the same time they have are know for noting wanting to work on older dailys. A buddy took his Chevy car to the dealership for a vaccum leak and they told him to buy a new car lol. They just didn't wanna work on it so he did it himself, took the car back and argued with the service manager and they admitted it and compt the price of the parts he used. So I took what they say with a grain of salt. I took the truck because I wanted them to look at the wiring and find the break but they didn't want to mess with it.
Another dealership is a possibility I'll try, but I know there is some good knowledge on this form.
Has anyone had any luck with getting rid of these codes?

 

[redheadedrod]

You should list the codes you have so we can better help you out.

I suspect your truck was in a flood if you have that many CEL codes. If your engine runs now without any noise then it is likely not an issue with the engine. 2008 had an issue with AFM that takes out the Lifters but if the engine runs you can do a AFM delete and prevent this from happening. However if you do the delete I would suggest replacing ALL of your lifters, not just the AFM lifters. AFM delete more or less requires new camshaft, new Lifters to replace the AFM units and a new Valley cover since that contains the solenoids that make everything else work. You MAY be able to just change the camshaft and the Valley cover to accomplish this and leave the AFM lifters in place but would strongly suggest replacing the lifters. Also requires reprogramming to disable the AFM in the PCM. (Since you are having lifter tick this is a sign that a FULL AFM delete is in the future for you. If you can do it yourself you can save a butt load of money because it will be somewhat time consuming.)

Most auto parts stores can read the main codes.

You may benefit from doing the "big three" wire upgrades at this time. If your truck is hitting a bump and shutting off you have something loose and most times it is related to a main ground or power wire.

The fuse box is easy to disassemble. It is possible that rodents got into it and ate wires since there is a bunch of space under neath it. But don't do work on this without disconnecting the negative cable.

Also, if you have a bad lifter then doing the AFM delete should fix your engine as long as the engine its self has not been damaged yet. Doing the AFM delete kit is not much more complex than replacing the head gaskets. Basically you remove the heads to get to the lifters, change the valley cover and replace the camshaft. So replacing the camshaft adds a bit of complexity but nothing major. Plenty of help out there to walk you through doing what needs to be done if you are at all mechanically inclined. If you pay a normal shop to do it you are going to cry at the cost they charge you if they do it right. Dealer was probably accurate if you were going to do it there that would be cheaper to just put a different engine in the truck but they would want a new GM engine which would be very costly. And would still have same AFM issue.

If you are unsure if you can do this or not then I woulds strongly suggest picking up a rebuilding guide for LS engines. They explain everything that you need to do to totally rebuild the engine. Obviously you don't need to do that but it certainly helps for even just redoing the top end.

I have never rebuilt an engine before and I am doing mine. I have the following two books that help dramatically:
How to rebuild GM LS-Series Engines
ISBN: 9781932494600

How to build and modify GM LS-Series Engines
ISBN: 978-0-7603-3543-7

 

[EXT4ME]

I am just confused why codes that point to the fuel system would warrant a new engine.

Maybe I'm just not understanding something here.

I do not take any of my vehicles to a dealer service department unless it is for a factory recall repair.

I have found several local, capable and trustworthy mechanic shops that I tend to use for repairs I can not or do not want to perform myself.

I have saved a lot of time and money along the way by doing so.

Perhaps you could ask around and see what the people around you prefer.

Maybe a fresh set of eyes would help.

 

[frank1]

What are the Codes ?

 

[ygmn]

What are the Codes ?

CHECK ENGINE codes.

When check engine light is on the computers store codes.
These codes can be followed in service manuals and make it easier to repair then guessing.

 

[AlonzoA]

You should list the codes you have so we can better help you out.

I suspect your truck was in a flood if you have that many CEL codes. If your engine runs now without any noise then it is likely not an issue with the engine. 2008 had an issue with AFM that takes out the Lifters but if the engine runs you can do a AFM delete and prevent this from happening. However if you do the delete I would suggest replacing ALL of your lifters, not just the AFM lifters. AFM delete more or less requires new camshaft, new Lifters to replace the AFM units and a new Valley cover since that contains the solenoids that make everything else work. You MAY be able to just change the camshaft and the Valley cover to accomplish this and leave the AFM lifters in place but would strongly suggest replacing the lifters. Also requires reprogramming to disable the AFM in the PCM. (Since you are having lifter tick this is a sign that a FULL AFM delete is in the future for you. If you can do it yourself you can save a butt load of money because it will be somewhat time consuming.)

Most auto parts stores can read the main codes.

You may benefit from doing the "big three" wire upgrades at this time. If your truck is hitting a bump and shutting off you have something loose and most times it is related to a main ground or power wire.

The fuse box is easy to disassemble. It is possible that rodents got into it and ate wires since there is a bunch of space under neath it. But don't do work on this without disconnecting the negative cable.

Also, if you have a bad lifter then doing the AFM delete should fix your engine as long as the engine its self has not been damaged yet. Doing the AFM delete kit is not much more complex than replacing the head gaskets. Basically you remove the heads to get to the lifters, change the valley cover and replace the camshaft. So replacing the camshaft adds a bit of complexity but nothing major. Plenty of help out there to walk you through doing what needs to be done if you are at all mechanically inclined. If you pay a normal shop to do it you are going to cry at the cost they charge you if they do it right. Dealer was probably accurate if you were going to do it there that would be cheaper to just put a different engine in the truck but they would want a new GM engine which would be very costly. And would still have same AFM issue.

If you are unsure if you can do this or not then I woulds strongly suggest picking up a rebuilding guide for LS engines. They explain everything that you need to do to totally rebuild the engine. Obviously you don't need to do that but it certainly helps for even just redoing the top end.

I have never rebuilt an engine before and I am doing mine. I have the following two books that help dramatically:
How to rebuild GM LS-Series Engines
ISBN: 9781932494600

How to build and modify GM LS-Series Engines
ISBN: 978-0-7603-3543-7

Currently showing CEL codes
P0230
P069E
P025A

I've started reviewing what's needed for lifters replacement to include the vlom. I'm okay with doing that work just not replacing the camshaft yet. Seems like that might be outside my ability. I'm definitely going to look into these books you mentioned, thanks for that. Also what's the "big three" wire upgrades?

 

[AlonzoA]

What are the Codes ?

I am just confused why codes that point to the fuel system would warrant a new engine.

Maybe I'm just not understanding something here.

I do not take any of my vehicles to a dealer service department unless it is for a factory recall repair.

I have found several local, capable and trustworthy mechanic shops that I tend to use for repairs I can not or do not want to perform myself.

I have saved a lot of time and money along the way by doing so.

Perhaps you could ask around and see what the people around you prefer.

Maybe a fresh set of eyes would help.

I agree with you, but anyone around that's worth anything is slammed busy for weeks, I guess I may just have to wait some.

 

[AlonzoA]

Don't know if this helps any but I can clear my CEL (obdlink mx+) and the truck will run okay till an uphill portion where I need to get on the gas some. I live on a hill so can't avoid it lol. The truck will studder and jerk and the three codes p0230, p069E, p025A all show up at once.

 

[AlonzoA]

I could just get another truck but this is my first Avalanche and is awesome I have three kids, a short driveway, and find myself moving 8ft long things all the time, lol. Seriously why isn't there a new truck with a mid-gate it's perfect. Even with all this headache I'll buy another one for sure.

 

[ygmn]

DUCK DUCK is your Friend:

Chevrolet Silverado 1500: p069e and p025a codes given 07 silverado...

P069e and p025a codes given 07 silverado... replace fuel pump... still getting p069e code... runs fine for a while then - Answered by a verified Chevy Mechanic

www.justanswer.com

Code P0230 Chevrolet: Fuel Pump Relay Control Circuit

When you turn the ignition switch to the ON position, the Powertrain Control Module (PCM) activates the in-tank fuel pump. The fuel pump remains on as

www.autocodes.com

Code P069E Chevrolet: Fuel Pump Control Module Requested MIL Illumination

The Fuel Pump Control Module uses the serial data network to signal the Engine Control Module (ECM) that the Fuel Pump Control Module is requesting

www.autocodes.com

Code P025A: Fuel Pump Module Control Circuit/Open

The Powertrain Control Module (PCM) monitors the Fuel Pump Command (FPC) circuit for a concern. When the PCM commands the Fuel Pump (FP) ON, the PCM is

www.autocodes.com

ENjoy the reading

 

[AlonzoA]

DUCK DUCK is your Friend:

Chevrolet Silverado 1500: p069e and p025a codes given 07 silverado...

P069e and p025a codes given 07 silverado... replace fuel pump... still getting p069e code... runs fine for a while then - Answered by a verified Chevy Mechanic

www.justanswer.com

Code P0230 Chevrolet: Fuel Pump Relay Control Circuit

When you turn the ignition switch to the ON position, the Powertrain Control Module (PCM) activates the in-tank fuel pump. The fuel pump remains on as

www.autocodes.com

Code P069E Chevrolet: Fuel Pump Control Module Requested MIL Illumination

The Fuel Pump Control Module uses the serial data network to signal the Engine Control Module (ECM) that the Fuel Pump Control Module is requesting

www.autocodes.com

Code P025A: Fuel Pump Module Control Circuit/Open

The Powertrain Control Module (PCM) monitors the Fuel Pump Command (FPC) circuit for a concern. When the PCM commands the Fuel Pump (FP) ON, the PCM is

www.autocodes.com

ENjoy the reading

Thanks for the links

 

[redheadedrod]

They all seem to be related to the fuel pump control module.

If it were me I would do the big three upgrade. (Google search Big three upgrade Silverado)
Basically you are increasing the size of the wiring from the battery to your vehicle to allow less voltage drop due to undersized wiring.
In my vehicle I did this a little differently.
I left the original wiring in place with one exception. The alternator wire. I removed this wire all together. Since this goes to a red power tap that has a bracket bolted to the alternator bracket I removed this tap and bolted the two main wires together. These wires only go to the starter so my bolting them together then taping the connection to insulate it doesn't harm anything. I will likely replace this wire when I change out the motor in the fall with a 1 piece upgraded wire.
I removed the bracket bolted to the alternator bracket and ran a 1/0 gauge wire from the battery to one of the bolts. I ran a second 1/0 gauge wire to the firewall ground from the second bolt. This allows a very good connection to the engine block for ground as well as to the firewall. And no such thing as too big a wire. When you consider the whole body and frame of your truck is a ground wire...
I ran a 1/0 gauge wire to my alternator from the battery. This was really overkill when you consider the original alternator wire was 10gauge. My wire was getting really hot though. And with my dual alternator setup I have a breaker between the power on both alternators so this wire gets used to jump my main battery from the secondary battery when needed by closing a breaker. I should have run a bigger wire to the main fuse panel as well but I did not. That will be upgraded when I do my engine swap. It is normally an 8 gauge wire. Going to a 4 gauge wire should probably be sufficient for powering everything normally powered. Biggest thing is upgrading the ground wires to the firewall and to the block, the power cable to the fuse panel. Upgrading the wire to the starter can help insure the starter works better as well. The normal "big three upgrade" MAY be different than what I did. My secondary battery is connected to the same bolts on the alternator bracket as well as to the firewall by the bracket for ground and a 1/0 gauge wire running to the 250+ amp alternator. This one powers my ~2000 watt stereo system but I ran 1/0 gauge wires directly to the fuse panels to power these. Probably far beyond what you want to do.

Find the fuel pump module. I would check the connectors on it and make sure they are not corroded or damaged. If you can find a fuel pump module cheap I would consider replacing it otherwise I wouldn't bother messing with it yet. You also want to track down the ground for it as well and make sure it is solid. You should be able to google search and find it. If not let me know and I can look it up.

If this is all fine and dandy then you likely have an issue similar to what I had with my '94 Caprice. In my caprice the fuel pump went out... When it was close to going out it was sucking a lot of power through the power wiring and actually burnt the ground wire to it. In that vehicle the ground was shared with the tail lights so every time I hit the brakes the engine stalled out. When I checked the fuel pressure I only had 15psi on a system that was supposed to have 40+. The fix in my case was a new fuel pump with all of the attached wiring. Once I replaced this then the fuel pump worked great. I also had to replace the wire at a junction point because it actually melted the connector. I should go back and replace the harness but it worked so I didn't mess with it. So I would suspect your fuel pump wiring is suspect and may require replacing it. Likely just in the fuel tank. If your fuel tank level has been jumping all over the place at all this would be the likely suspect.

Maybe someone else has an idea but to me it seems like the fuel pump isn't getting enough power for some reason.

 

[redheadedrod]

Also about the cam shaft... The cam shaft is easy... Pulling the heads is way more complicated than pulling the cam shaft.

Basically pull the harmonic balancer then the front cover... Once those are off you can remove the bolt(s) that are on the camshaft gear. You either have a 3 bolt or 1 bolt gear. You want to mark where the gear lines up on the block to make it easier to install new camshaft. Make a mark with a marker on both the gear and the block should be sufficient. Once you remove the gear don't move the crankshaft. The chain can stay in place.
Once you have the gear off you should see a camshaft cover plate. This plate comes off with like 5 bolts. You need a couple long bolts to pull the old camshaft out. (If the lifters were in place you have to go through a process to lift them and lock them out. But since you pulled them out to replace, no problem... )

You wiggle the camshaft out using the long bolts to help balance the camshaft so you are sliding it out and not trying to take the bearings out with it.

New crank shaft, you slather with assembly lube, put the long bolts back on it and slowly slide the new cam shaft in similar to how you pulled the old one out. Once it is in place you remove the bolts, install a new camshaft cover, then put the gear back on. You want to make sure the gear lines up with the mark you made on the block. You needed to have the chain on the gear when you were sliding it back on. As long as you lined the gear back up where the original camshaft was you should be fine. Assuming you have a camshaft that doesn't need to be degreed. You can get instructions from the camshaft manufacturer as well most times.

You CAN elect to replace the oil pump and timing set as well at this point but you may or may not be able to get the pickup tube off the pump without dropping the pan.

Once those are back together you can put the front cover back on. Anything I have seen suggests putting the cover back on and getting it close, putting the harmonic balancer back on but don't torque it down all the way yet. Bolt front cover down and all set. Torquing the balancer can be done later after the heads are back on. You need a new front cover seal, crankshaft seal, crankshaft bolt.

I don't believe you can replace the lifters without replacing the camshaft. Thought I read that because they have hydraulic openings to feed the lifters they are slightly different and are not compatible with standard lifters.

 

[AlonzoA]

Thanks redhead for the details. I'm currently working through the fuse box ensuring all connections are good there might try to replace the junction box to rule out the internal fuses, after that I'll move to the wiring upgrades.
I replaced the fuel pump a few weeks ago. I knew the original was in it, I wasn't getting crazy fuel levels but I was just shooting in the dark looking for a fix. When I had the tank dropped I did inspect the wiring back there and everything looked good. Which is why I'm at the front of the truck looking at where the harness comes into the fuse block.
The FSCM is new replaced 4 months ago, and I have been over the connections which again nothing is jumping out to me. I'm just learning how to test these wires, the one thing I really need to find is a complete wiring schematic of the fuel module circuit so I can stop guessing but Google is failing me.
After reading that cam walk through I'm ready to do some performance stuff. If I get these codes gone then im going to get a hot cam and rebuild the top. That sounds like more fun than hunting down wires and It's time for my Avalanche to be more than stock.

 

[AlonzoA]

Thanks to alldata i think i found my wire, P4. I plan on tracing this back today hopefully i find a break.

 

[davenay67]

Late to the party! Did you ever resolve your remaining 3 CEL codes?

I also am in the middle of troubleshooting the same codes. From all of my research so far, it seems like the cause can occur in quite a few places.

I originally had the crank-no start condition, which I traced to a faulty FSCM using the GMFlash diagnosis page. Installing the ne unit and the truck fired up straight away. Many months later I got the same crank/no start condition. By luck I found that jiggling the large plug to the FSCM got the truck started. I cleaned the pins on both the FSCM and the plug using electrical contact cleaner and used di-electic grease upon reinstall. This worked for about 3 months.

Yesterday I was driving and the truck developed this new issue where it would just cut out suddenly for no reason. Not much fun when this happens on a freeway!! It fortunately restarted and I could limp home. I was getting P069E and P025A when this was happening. Messing around at home and I once again got he P0230 code and the subsequent crank/no start condition.

I am 99% certain my issue lies in the wiring or pin connections between the FSCM and the large plug. I intend to take out each wire and inspect / clean / repair individually. The same codes could easily be caused by the same wires with a connection issue on a different part of the vehical. The playing field for where the actual issue lies is large on this problem.

It's cold here in Chicago right now, and the though of lying on a frozen driveway in freezing weather is not appealing. It couldn't have waited until Spring to act up?

 

[gmAtech]

Make sure the braided cable from the back of the head to the firewall for the body ground is good. If it's loose or turned green it can cause crazy electrical problems.