P0521 on the 2005 GMC Envoy
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
Nobody has written a description of this code yet.
| PIP4786B | 2017-08-15. Service bulletin. This Preliminary Information communication provides information to the technician about vehicles that may have low oil pressure message. Technician may also find a Diagnostic Trouble Code P0521 in the Engine Control Module. Technician should follow all published Service Information diagnosis. When using a scan tool if the oil pressure is low but the oil pressure at the oil filter housing is correct, technician should inspect the Valve Lifter Oil Filter for debris/sludge that could be restricting oil flow to the oil pressure sensor. Technician should remove the Valve Lifter Oil Filter and clean it. If the Valve Lifter Oil Filter cannot be cleaned replace it. |
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| PIP4786A | 2017-08-15. Service bulletin. This Preliminary Information communication provides information to the technician about vehicles that may have low oil pressure message. Technician may also find a Diagnostic Trouble Code P0521 in the Engine Control Module. Technician should follow all published Service Information diagnosis. When using a scan tool if the oil pressure is low but the oil pressure at the oil filter housing is correct, technician should inspect the Valve Lifter Oil Filter for debris/sludge that could be restricting oil flow to the oil pressure sensor. Technician should remove the Valve Lifter Oil Filter and clean it. If the Valve Lifter Oil Filter cannot be cleaned replace it. |
| PIP4786C | 2016-10-20. Service bulletin. THIS PRELIMINARY INFORMATION COMMUNICATION PROVIDES INFORMATION TO THE TECHNICIAN ABOUT VEHICLES THAT MAY HAVE LOW OIL PRESSURE MESSAGE. TECHNICIAN MAY ALSO FIND A DIAGNOSTIC TROUBLE CODE P0521 IN THE ENGINE CONTROL MODULE. TECHNICIAN SHOULD FOLLOW ALL PUBLISHED SERVICE INFORMATION DIAGNOSIS. WHEN USING A SCAN TOOL IF THE OIL PRESSURE IS LOW BUT THE OIL PRESSURE AT THE OIL FILTER HOUSING IS CORRECT, TECHNICIAN SHOULD INSPECT THE VALVE LIFTER OIL FILTER FOR DEBRIS/SLUDGE THAT COULD BE RESTRICTING OIL FLOW TO THE OIL PRESSURE SENSOR. TECHNICIAN SHOULD REMOVE THE VALVE LIFTER OIL FILTER AND CLEAN IT. IF THE VALVE LIFTER OIL FILTER CANNOT BE CLEANED REPLACE IT. |
3 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.