DTC P0521 4.6L and 4.4L
Circuit Description
The engine oil pressure (EOP) sensor changes voltage based on engine oil pressure. The engine control module (ECM) monitors the signal circuit of the EOP sensor. When the oil pressure is high, the sensor voltage is high, and the ECM senses a high signal voltage. When the oil pressure is low, the sensor voltage is low, and the ECM senses a low signal voltage. The ECM sends the EOP information to the instrument panel cluster (IPC) via the GMLAN serial data circuit.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0521 Engine Oil Pressure (EOP) Sensor Performance.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The ECM does not detect a change in the EOP of at least 34.5 kPa (5.0 psi) over a predetermined variance of the engine speed.
Action Taken When the DTC Sets
| • | The ECM records the operating conditions at the time the diagnostic test fails. The ECM displays this information in the Failure Records on the scan tool. |
| • | The IPC illuminates the EOP indicator. |
Conditions for Clearing the DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction-free warm-up cycles. |
| • | The ECM receives a clear code command from the scan tool. |
Diagnostic Aids
Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.
Refer to Testing for Intermittent Conditions and Poor Connections .
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics Connector End View Reference: Engine Control Module Connector End Views for the 4.6L engine, Engine Control Module Connector End Views for the 4.4L engine or Inline Harness Connector End Views | ||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||
2 |
Does the Engine Oil Pressure Sensor parameter display values that vary within the specified values when idling and accelerating the engine? | 0.7-2.5 V 880 kPa (127.6 psi) - 8 kPa (1.16 psi) | Go to Diagnostic Aids | Go to Step 3 | ||||
3 | Replace the engine oil pressure (EOP) sensor. Refer to the following:
Did you complete the replacement? | -- | Go to Step 4 | -- | ||||
4 |
Does the DTC reset? | -- | Go to Step 2 | System OK | ||||
DTC P0521 3.6L LY7
Circuit Description
The engine oil pressure (EOP) sensor changes voltage based on engine oil pressure. The engine control module (ECM) monitors the signal circuit of the EOP sensor. When the oil pressure is high, the sensor voltage is high, and the ECM senses a high signal voltage. When the oil pressure is low, the sensor voltage is low, and the ECM senses a low signal voltage. The ECM sends the EOP information to the instrument panel cluster (IPC) via the GMLAN serial data circuit.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0521 Engine Oil Pressure (EOP) Sensor Performance Check High and Low
Conditions for Running the DTC
| • | The engine is idling at less than 640 RPM and EOP sensor performance check is high. |
| • | The engine is running at greater than 1,520 RPM and EOP sensor performance check is low. |
Conditions for Setting the DTC
| • | The engine oil pressure is greater than 880 kPa (127.6 psi). |
| • | The engine oil pressure is less than 8 kPa (1.16 psi). |
Action Taken When the DTC Sets
| • | The ECM records the operating conditions at the time the diagnostic test fails. The ECM displays this information in the Failure Records on the scan tool. |
| • | The IPC illuminates the EOP indicator. |
Conditions for Clearing the DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction-free warm-up cycles. |
| • | The ECM receives a clear code command from the scan tool. |
Diagnostic Aids
Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.
Refer to Testing for Intermittent Conditions and Poor Connections .
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics Connector End View Reference: Engine Control Module Connector End Views for the 3.6L engine or Inline Harness Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Does the Engine Oil Pressure Sensor parameter display values that vary within the specified values when idling and accelerating the engine? | 880 kPa (127.6 psi) 8 kPa (1.16 psi) | Go to Diagnostic Aids | Go to Step 3 |
3 | Replace the engine oil pressure (EOP) sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement for the 3.6L engine. Did you complete the replacement? | -- | Go to Step 4 | -- |
4 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
