GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • EN-47971 Oil Pressure Gage Adapter
    • J 21867 Pressure Gage
    • J-21867-16 Oil Pressure Adapter

    Object Number: 1658100  Size: SH

    Important: This test is performed to verify the operation of the active fuel management oil pressure relief valve located in the oil pan. Refer to Lubrication Description .

  1. Remove the oil filter and install the EN-47971  (1).
  2. Install the J 21867  (2), or equivalent, to the EN-47971  (1).

  3. Object Number: 1658103  Size: SH
  4. Remove the oil pressure sensor and install the J-21867-16 .

  5. Object Number: 1658106  Size: SH
  6. Install the J 21867  (1), or equivalent, to the J-21867-16  (2).
  7. Run the engine and measure the engine oil pressure while observing both gages.
  8. Operate the throttle, as required, to increase and decrease the engine oil pressure.

    • With the engine running and the lower pressure gage (2) measuring below 379 kPa (55 psi), both gages should display the same pressure reading. If the readings are not the same and the lower gage (2) has a higher reading, the active fuel management oil pressure relief valve is stuck in the open position or the valve lifter oil manifold filter is plugged.
    • With the engine running and the lower pressure gage (2) measuring above 379 kPa (55 psi), the upper gage (1) should display no greater than 379-517 kPa (55-75 psi). If the reading on the upper gage (1) is greater than 517 kPa (75 psi), the active fuel management oil pressure relief valve is stuck in the closed position.
  9. Repair, as required.