WARNING: This page is about a different car, the 2003 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
Measure clearance between seal ring and ring groove.
Standard clearance:
0.10 - 0.25 mm (0.0039 - 0.0098 in)
Wear limit:
0.25 mm (0.0098 in)
If not within wear limit, replace oil pump cover assembly.
Fig 1: Measuring Clearance Between Seal Ring And Ring Groove