Chevy Silverado and GMC Sierra Forum banner
1 - 20 of 172 Posts

·
Registered
Joined
·
92 Posts
Discussion Starter · #1 ·
2009 5.3 Crew cab with AFM and 6-speed auto

Was on my way to work this morning when all of the sudden i got a warning and dinging. Looked down and I had very little oil pressure. Stopped and shut down. Checked and I had oil. Let it sit a while started it back up, hey,.. have pressure.. hmm. Started to drive and it seemed that as the engine heated up, you could watch the pressure drop until I got the warning.

Any ideas? Im thinking faulty sensor as I have oil and pressure at start-up???
 

·
Registered
Joined
·
13,366 Posts
I agree, check the oil pressure sensor. The are known to go bad and leak, causing a faulty reading. If in doubt, have the pressure checked with a real gauge.
 

·
Registered
Joined
·
8,415 Posts
#PIP4786: Low Oil Pressure Message Light - Inspect Valve Lifter Oil Filter - (Apr 5, 2010)
Subject: Low Oil Pressure Message/Light - Inspect Valve Lifter Oil Filter

Models: 2007 Cadillac Escalade

Built before April 1, 2006 with 6.2L L92 Engine

(These engines were built with AFM Hardware but the AFM system was disabled.)

2009 Buick Lacrosse Super, Allure Super (Canada Only)

2005-2007 Buick Rainier

2010 Chevrolet Camaro SS

2007-2010 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007-2009 Chevrolet Impala

2005-2009 Chevrolet Trailblazer

2007 Chevrolet Monte Carlo

2007-2010 GMC Sierra, Yukon

2005-2009 GMC Envoy

2007-2008 Pontiac Grand Prix

2008-2009 Pontiac G8

2005-2009 Saab 97x

With an AFM (Active Fuel Management) V8 Engine RPO: L76, L94, L99, LC9, LFA, LH6, LMG, LS4, or LY5


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:


Some customers may complain of a low oil pressure message/light on the dash and a technician may find a P0521 DTC in the ECM.

Recommendation/Instructions:


If this concern is encountered, follow SI diagnosis. If it indicates that the Tech 2 oil pressure parameter is low but proper oil pressure is present at the oil filter housing, inspect the Valve Lifter Oil Filter for debris/sludge that could be restricting oil flow to the oil pressure sensor before replacing any parts.
Follow the Valve Lifter Oil Filter Removal and Installation Procedure to remove the filter for inspection. If the filter is plugged, it can normally be cleaned with brake/contact cleaner and light shop air. If it cannot be cleaned for some reason, replace it using the part number listed in the parts catalog. Do not replace the complete Valve Lifter Oil Manifold just because the filter is plugged.

#452 - Valve Lifter Oil Filter
Screen shot 2012-11-05 at 7.28.34 PM.png

 
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.  WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
 

Attachments

·
Registered
Joined
·
92 Posts
Discussion Starter · #4 ·
Seems like everything I am reading and talking to are also pointing to the Pressure Switch. I believe this too as the engine temp did not rise and from what it appears, I was still getting oil through the engine.

This is the sensor located on the backside of the intake, correct?
 

·
Registered
Joined
·
92 Posts
Discussion Starter · #6 ·
Alright, Thanks. All local parts stores were out, so had to order one. Should be in tomorrow.
 

·
Registered
Joined
·
31 Posts
I had the same problem right after I bought the truck ( used, auction, can't return it, you buy it you own it type of deal ). In first 2 minutes of driving it, I got low oil press light and sounds....Crap, I thought engine was shot....Anyway, towed to garage and started with oil change. Everything was back to normal. I suggest you change the oil/filter first.
 

·
Registered
Joined
·
294 Posts
I've had same issue on my 2009 GMC 5.3 with AFM. I took to dealer and got switch replaced. Issue came back. Took to my automotive guy and he back blew the hoses with air. Issue went away for a week and came back. I took back to my local guy and did a full oil change and filter change. If it comes back again Ill need to look at the valves and see if they're faulty.
 

·
Registered
Joined
·
2,542 Posts
Please keep us updated about the this situation. Let us know if any issues in resolvent the situation with your dealership. Feel free to contact us privately but please include your VIN#, name, situation, contact information, dealership, and mileage. I hope this is resolved quickly for you. Regards.

Matt,

GM Customer Assistance
 

·
Registered
Joined
·
294 Posts
Update on my 2009 GMC 5.3 with AFM. I took to dealer and got switch replaced. Issue came back. Took to my automotive guy and he back blew the screens with air. Issue went away for a week and came back. I took back to my local guy and did a full oil change and filter change. ... It did not come back for 2 weeks. I did take to another dealer and they replaced the screen (they said it was plugged and clogged) ... my question is ... Now how do I prevent this in the future from happening again?
 

·
Registered
Joined
·
4 Posts
Boucher187 said:
Update on my 2009 GMC 5.3 with AFM. I took to dealer and got switch replaced. Issue came back. Took to my automotive guy and he back blew the screens with air. Issue went away for a week and came back. I took back to my local guy and did a full oil change and filter change. ... It did not come back for 2 weeks. I did take to another dealer and they replaced the screen (they said it was plugged and clogged) ... my question is ... Now how do I prevent this in the future from happening again?
Hi Boucher187,

I ran into the same issue with my truck. I took it to the dealer for a check engine light the code was P0521. They told me they would have to replace my oil pressure switch. They replaced it about a month ago sense I have taken it 3 more times for the same code they keep telling me the code was not erased properly, I don't think that's is the case. After reading your post I was wondering if your check engine light came back on? I was also wondering what screen got replaced?

Thank you,
Dave
 

·
Registered
Joined
·
294 Posts
sierra_dave said:
Hi Boucher187,

I ran into the same issue with my truck. I took it to the dealer for a check engine light the code was P0521. They told me they would have to replace my oil pressure switch. They replaced it about a month ago sense I have taken it 3 more times for the same code they keep telling me the code was not erased properly, I don't think that's is the case. After reading your post I was wondering if your check engine light came back on? I was also wondering what screen got replaced?

Thank you,
Dave
Here is what I was able to take to the Dealer and get my issue corrected. This stopped the Low Oil Pressure Issue.

#PIP4786: Low Oil Pressure Message Light - Inspect Valve Lifter Oil Filter - (Apr 5, 2010)
Subject: Low Oil Pressure Message/Light - Inspect Valve Lifter Oil Filter

Models: 2007 Cadillac Escalade

Built before April 1, 2006 with 6.2L L92 Engine

(These engines were built with AFM Hardware but the AFM system was disabled.)

2009 Buick Lacrosse Super, Allure Super (Canada Only)

2005-2007 Buick Rainier

2010 Chevrolet Camaro SS

2007-2010 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007-2009 Chevrolet Impala

2005-2009 Chevrolet Trailblazer

2007 Chevrolet Monte Carlo

2007-2010 GMC Sierra, Yukon

2005-2009 GMC Envoy

2007-2008 Pontiac Grand Prix

2008-2009 Pontiac G8

2005-2009 Saab 97x

With an AFM (Active Fuel Management) V8 Engine RPO: L76, L94, L99, LC9, LFA, LH6, LMG, LS4, or LY5


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:


Some customers may complain of a low oil pressure message/light on the dash and a technician may find a P0521 DTC in the ECM.

Recommendation/Instructions:


If this concern is encountered, follow SI diagnosis. If it indicates that the Tech 2 oil pressure parameter is low but proper oil pressure is present at the oil filter housing, inspect the Valve Lifter Oil Filter for debris/sludge that could be restricting oil flow to the oil pressure sensor before replacing any parts.
Follow the Valve Lifter Oil Filter Removal and Installation Procedure to remove the filter for inspection. If the filter is plugged, it can normally be cleaned with brake/contact cleaner and light shop air. If it cannot be cleaned for some reason, replace it using the part number listed in the parts catalog. Do not replace the complete Valve Lifter Oil Manifold just because the filter is plugged.

#452 - Valve Lifter Oil Filter

 
 

Screen shot 2012-11-10 at 12.46.31 PM.png (46.29 KiB) Viewed 4227 times

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.  WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
 

·
Registered
Joined
·
11 Posts
I also just had this happen to me, here's what happened: First my check engine light came on, 2 days later the light turned off by itself, the day after that it came back on and about 25 minutes into my drive I hear a warning sound, I got the "low oil pressure, shut down engine" warning so I quick pulled over and shut it off. I had oil but I added half a qt. to see if that would do anything...didn't work.
But shutting it off and waiting a few minutes , starting it back up you'd get pressure back and within a few minutes would go back down to zero and I'd get the warning again.

So I towed it to have my stepdad take a look, turns out the check engine light was in correlation with whatever was going on with the oil pressure (which is what I figured), instead of replacing the sensor he just removed the little screen on the bottom of it ( I think he said it was called a lifter screen or something like that) so I drove it home without any trouble and all the way to work today without problems so I'm hoping it was just that little screen causing the issue!

On a side note- do you guys think I should replace that screen with a new one or just keep it out to prevent it from happening again??
 

·
Registered
Joined
·
4 Posts
Hello, I'm new to this forum. I was having symptoms consistent with others on my 2010 Silverado 5.3L w/ 45K - drop in pressure, shut engine down warning, etc. The first time this happened, it made me pretty nervous. I checked the oil, and since it wasn't making any sounds like it had no oil pressure, just drove it a short distance home. I changed the oil, pressure came up, and it operated as it should... thought it was faulty filter or something. Then it happened again about 2,500 miles later. I did some research and kept coming across this and similar threads. I was a little skeptical of the switch being bad - seems like dealers get the green light to change them just because the truck is throwing the P0521 code. This is just my opinion.

I'm not a stranger to vehicles, but am by no means a mechanic. I can do general maintenance, brakes, etc. I'm not going to get into it, but have decided the dealer will not be getting any more of my money to fix something that should not be broken. There's plenty of posts that say removal of the intake is required, so I was a bit hesitant at first. After taking the engine cover off and looking at it, I tried to get at it without intake removal. This worked, and below is what I did and some pics of what I found.

First of all, having fairly large hands made this even more difficult. If you are not feeling patient, do not try this - you can't really see much of what you are doing and have very little space to do it in. As seen in the picture below, there is a plastic cover that obstructs direct access to the oil pressure sending unit. I left it there, and hooked the vacuum line that was in my way over the top of it.

After removing the connector, there was enough clearance to slip a socket over the switch. The vacuum line above causes some clearance issues, so I had to use a swivel also. My setup was socket, 1/2 to 3/8 adapter, swivel, extension, ratchet. With the vacuum line in the way, I had to put the socket over the switch first, and then assemble the rest one at a time.

Once loosened, the switch comes out easily by hand. Below the sending unit is the screen. I fished it out using a pick with a curved end. Nothing was holding it in place - seems to just sit in there. It came out looking very nasty- clogged with sludge and metal shavings stuck to the outside (dealer would probably explain this as normal operating condition). I had to soak it in penetrating oil, then sprayed it with contact cleaner and compressed air. I would say that got it about 95% clean.

I put the screen back in, put the old switch back in (don't forget Teflon goo for threads), put everything back together, and cleared the code P0521 oil pressure circuit code. Be careful when putting the switch back in... it's the kind of thing that can crack pretty easy if you apply too much force or are not on it evenly (remember - can't see it & using swivels/adapters). Now, I have oil pressure and no codes are present. After taking it for a test drive in mixed conditions, the afm seems to behave a little better too. In all, I spent about an hour doing this and only had to purchase the oil pressure switch socket.

Good luck to anyone that tries this. Below are links to some pictures in my gallery:

Warning lights and DIC text:


Behind plastic shield - top view of oil pressure sending switch:



View from driver side looking toward rear of valve cover area:


AFM screen - lower part is clogged with sludge and outside has some metal filings:


Tools:
 

·
Registered
Joined
·
294 Posts
Wow. Excellent write up for a fix for this issue. I took my truck to my local mechanic and he did the same fix. Check and make sure your truck is not beginning to burn Oil. I first noticed my drop in Oil Pressure and right after that is when I began to BURN OIL.
 

·
Registered
Joined
·
4 Posts
Now that you mention burning oil, I thought I saw a puff of blue from the tailpipe when I started it a couple of weeks ago. Haven't seen it since, so just thought it was me being paranoid. Are you seeing it on starts, cold starts, or all the time? How much would you estimate it's using?

I changed the oil & filter about a 100 miles after cleaning the afm screen. I plan on cutting the filter open this week to see if there are any little metal surprises in there like there were in the afm screen. I stuck a magnet in the hole before putting the screen back in - it came out clean, but I'm still a little concerned over what was in the screen.
 

·
Registered
Joined
·
13 Posts
This thread is detailing exactly what happened to me this morning. He had indicated the screen issue when he was looking up the symptoms. We will find out.
 

·
Registered
Joined
·
13 Posts
tmark10, you indicated you needed to get a socket for the sensor. Is that a specialty socket or just a size you didn't have?
 
1 - 20 of 172 Posts
Top