gm tech 2 clone equivalent vehicle years 2000 thru 2016

GM states that some customers may complain of a low oil pressure message on the dash accompanied with a diagnostic code PO521. GM has identified the following vehicles (see Affected Vehicles below) equipped with AFM as potential candidates for the mentioned low oil pressure message.

The purpose of the filter screen is to help control contamination that can affect the AFM hydraulic system by filtering the oil that flows through the valve lifter oil manifold and its related solenoids. The screen (see illustration) is actually a filter for the valve lifters on those GM applications equipped with AFM. When the mentioned filter screen becomes restricted with debris/sludge, it restricts the oil supply to the oil pressure sensor, resulting in a low oil pressure warning/message. And he will be hesitant to let the lube shop service his vehicle in the future, as he has been convinced they created the problem. Naturally, the vehicle owner gets upset and approaches the lube shop requesting compensation for the cost of the repairs. Unfortunately, some customers are told the condition was due to the aftermarket oil filter and the incorrect lubricant installed in their vehicle. Familiar with the symptom and solution, the technician replaces the oil pressure sensor and a filter screen positioned beneath the sensor, which eliminates the low oil pressure message. When this fails, the vehicle is often sent to the dealer for further evaluation. In some cases, the customer encounters the low oil pressure message and has the oil and filter changed in an effort to correct the symptom. They may recommend some major engine repairs, which would not eliminate the mentioned symptoms.

When this procedure fails to solve the problem, they often assume oil pump related issues are at fault or serious engine related problems have occurred. Some technicians replace the oil pressure sensor in a futile attempt to eliminate the low oil pressure message. These symptoms often occur with no indication of a low oil pressure condition such as engine related noises. A low oil pressure message/light is becoming a common complaint on 2007-2016 GM vehicles equipped with a V8 engine and active fuel management (AFM), which is sometimes referred to as displacement on demand (DOD).

Gm tech 2 clone equivalent vehicle years 2000 thru 2016