Low Oil Pressure Light/Gauge - keywords 3.5 3.9 cup gage left low LZ4 LZE LZ9 plug

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Low oil pressure in left hand turns. Usually occurs after vehicle has accumulated some mileage, but generally seen before 10,000 miles have accrued on vehicle. Condition only occurs when making left hand turns.

Engine oil pump may have a loose/missing cup plug in the pump body. During left hand turns, oil will move away from the pump body, exposing the open hole in the pump body and causing the low oil pressure concern.

1. Verify engine oil is at proper level.
2. Duplicate condition and verify low oil pressure.
3. Remove oil pan and inspect oil pump body for missing cup plug. Location of plug is given in the below picture.

1. Inspect pump plug as indicated in above picture. If plug is missing, damaged or cocked, replace engine oil pump. Make sure to remove cup plug from engine oil pan before installing oil pan on vehicle.
2. GMPT Engineering has requested the WPC to return all replaced pumps for inspection until further notice.

Note: Make sure the cup plug is returned with the pump assembly if it was found in the oil pan

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.