GM Low Pressure Signal

Aug. 29, 2016
This bulletin applies to a number of GM vehicles produced between 2005 and 2010, equipped with an AFM (active fuel management) V8 engine. One example is the 2007-2009 Chevy Impala. Some customers may complain of a low oil pressure message/light on the dash. 

This bulletin applies to a number of GM vehicles produced between 2005 and 2010, equipped with an AFM (active fuel management) V8 engine. One example is the 2007-2009 Chevy Impala.

Some customers may complain of a low oil pressure message/light on the dash.

The technician may find DTC P0521 stored in the ECM. If this concern is encountered, follow service manual diagnosis. If it indicates that the Tech2 oil pressure parameter is low but proper oil pressure is present at the oil filter housing, before replacing any parts, inspect the valve lifter oil filter for debris/sludge that could be restricting oil flow to the oil pressure sensor.

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, replace it. Do not replace the complete valve lifter oil manifold just because the filter is plugged.

Sponsored Recommendations

Gain expert insight into today’s evaporative emission systems and why OE-matched EVAP components are crucial for performance and compliance. See how Standard® delivers precision...
There is a difference in gas fuel injectors. Learn why Under the Hood’s Russ Evans uses Standard Fuel Injectors on his customer’s vehicles.
Just following a few simple tips can improve your pneumatic tool's performance and provide years of safe, maintenance-free service. Dive in to see what you could apply to your...
Hear what senior autotechs have to say about the AIRCAT Nitrocat 1056-XL compact impact wrench. They’ll provide their reviews on tools they own and have been using every day on...

Voice Your Opinion!

To join the conversation, and become an exclusive member of Vehicle Service Pros, create an account today!