Should you encounter a fluctuating oil pressure gauge on certain GM pickups, namely the 2019–2020 Silverado 1500 and Sierra 1500 (particularly with the L3B 2.7L four-cylinder engine), there’s no need for alarm.

The trucks employ a variable displacement oil pump that, in certain driving conditions, may cause the oil gauge reading to drop or change quickly. This is normal.

Along with the aforementioned variable displacement pump, the engine utilizes an oil control solenoid valve operated by the Engine Control Module that’s mounted to the oil pump and varies oil pressure according to engine needs. As a result, the pressure may change quickly as engine speed or load changes. It may also change due to the outside temperature and oil viscosity.

Image
Oil gauge for vehicle equipped with L3B engine.

Any abnormal engine conditions will typically trigger a message in the Driver Information Center (DIC). In addition, a DTC may set and the oil pressure warning light may or may not illuminate, depending on the situation. If no DIC message appears, the engine and oil pressure gauge are likely operating as designed and no repairs should be attempted.

Image

VARIABLE OIL PRESSURE

The engine oil pressure control solenoid valve is used to control oil pressure inside the mechanical engine oil pump (shown on V8 engine RPOs L82, L84 and L87 in graphic below). The control module manages the commanded state of the solenoid valve based on the following inputs:

  • Engine speed
  • Calculated engine oil temperature
  • Engine oil pressure
  • Engine run time
Image

When the solenoid valve is commanded off, oil pressure is higher. When the solenoid valve is commanded on, oil pressure is lower.

CUSTOMER REMINDER

Remind your customers that their vehicle’s engine oil level, recommended viscosity and oil condition are critical for proper operation of the system. As a result, they should check the oil level regularly and follow all scheduled maintenance in their Owner’s Manual.