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07 Sierra- Low Oil Pressure & Code P0521

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#1 nerijusj



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Posted 06 May 2011 - 04:26 PM

Looking for some insight on this issue folks. I searched first, read a couple posts of 2011 silverados 5.3 with similar symptoms, but haven't seen any info on this issue on 07 (or 08 ) trucks.
Today I picked up the 07 sierra slt cc 110K miles at an auction. Went for a ride after. Check engine light was on, I thought not a biggie. Anyway, drove very nice until engine warmed up, then I got Low Oil Pressure light and alarm, pressure gauge dropped from normal 40ish psi to almost bottom. Pulled the check engine code P0521. Crap! Would this bellow posted bulletin be a fix for it? How hard it is to get to that Valve Lifter Oil Filter ( pictured below )? How hard is to replace oil pump-dropping oil pan? What am I looking at cost wise if dealer does work?

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.

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.

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

Posted Image
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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.

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Edited by nerijusj, 06 May 2011 - 04:55 PM.

#2 nerijusj



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  • 2 posts

Posted 07 May 2011 - 11:05 AM

Also, engine is running fine, no unusual sound or knocks. I'm thinking to start with an oil and filter change, then oil sending unit....Any thoughts?