There may be low oil pressure in the 5.3L V8 engine (RPO L84) or 6.2L V8 engine (RPO L87) on some 2019-2024 Silverado 1500, Tahoe, Suburban, Sierra 1500, Yukon; and 2021-2024 Escalade models. If the oil pressure relief valve inside the oil pump assembly (Fig. 1) is stuck, it may cause low oil pressure at idle and, as a result, the Check Engine MIL may be illuminated and DTC P0521 (Engine Oil Pressure Sensor Performance) may be set in the Engine Control Module (ECM).
On some vehicles, the engine oil pressure sensor or ECM may have been replaced during a prior service repair.
Fig. 1
Electrical or Oil Pressure Sensor Concerns
Begin diagnosis by following the flow chart for DTC P0521. Check that there are not any electrical or oil pressure sensor concerns before inspecting the oil pump. (Fig. 2)
Fig. 2
Oil Pressure Test
If there aren’t any electrical or oil pressure sensor issues, perform a mechanical oil pressure test using the Oil Pressure Gauge Kit. Testing must be done with the engine at idle and at a normal operating temperature. Refer to Oil Pressure Diagnosis and Testing in the appropriate Service Information. (Fig. 3)
Fig. 3
Oil pressure can vary greatly at the oil filter location vs. at the oil pressure sensor location using the adapter specified in the service procedure. A difference of up to 10 psi may be found when checking oil pressure at both locations during testing.
Oil Pressure Relief Valve
If the oil pressure reading is below 20 psi when measured at the oil sensor port, it may be due to a stuck oil pressure relief valve (Fig. 4, 1. stuck valve; 2. normal valve). inside the oil pump assembly.
At this point, it will be necessary to remove the oil pump for further inspection. If the valve is found to be stuck, replace the oil pump. Refer to Oil Pump Replacement in the appropriate Service Information.
Fig. 4
For additional information, including part numbers, refer to Bulletin #24-NA-173.
– Thanks to Bryan Salisbury
