P0521
DTC P0521, P0522, or P0523
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0521
- Engine Oil Pressure Sensor Performance
DTC P0522
- Engine Oil Pressure Sensor Circuit Low Voltage
DTC P0523
- Engine Oil Pressure Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The engine oil pressure sensor changes voltage based on the engine oil pressure. The engine oil pressure sensor is a 3-wire sensor comprised of the signal circuit, the low reference circuit and the 5V reference circuit. The engine control module (ECM) supplies 5 V to the engine oil pressure sensor via the 5V reference circuit and provides ground via the engine oil pressure sensor low reference circuit. The ECM monitors the signal circuit of the engine oil pressure sensor to determine the engine oil pressure sensor voltage is within the normal operating range of approximately 1-4 V. When the engine oil pressure is high, the engine oil pressure sensor voltage is high and the sensor senses a high signal voltage. When the engine oil pressure is low, the engine oil pressure sensor voltage is low and the ECM senses a low signal voltage. The ECM sends the engine oil pressure sensor information via High Speed CAN-Bus to the body control module (BCM). The BCM then sends the engine oil pressure sensor information via Low Speed CAN-Bus to the instrument cluster.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
P0521
* The engine oil pressure is out of its working range.
* The ECM does not detect a change in the engine oil pressure.
* The above condition is present over a predetermined variance of engine speed.
P0522
* The ECM detects a short to ground in the engine oil pressure signal circuit.
* The above condition is present for greater than 10 s.
P0523
* The ECM detects a short to voltage or an open circuit in the engine oil pressure signal circuit.
* The above condition is present for greater than 10 s.
Action Taken When the DTC Sets
The instrument cluster illuminates the service vehicle soon indicator.
Conditions for Clearing the DTC
The DTC becomes history when the conditions for setting the DTC are no longer present.
Reference Information
Schematic Reference
Instrument Cluster Schematics (Instrument Cluster Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
* Instrument Cluster Description and Operation (Instrument Cluster)
* Indicator/Warning Message Description and Operation (Indicator/Warning Message)
* Driver Information Center (DIC) Description and Operation (Driver Information Center (DIC))
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Engine running, observe the scan tool Engine Oil Pressure Sensor parameter. The reading should be between 103-241 kPa (15-35 PSI).
Circuit/System Testing
6 Cylinder Engine RPO LLT
1. Ignition OFF, disconnect the harness connector at the B37B Engine Oil Pressure Sensor.
2. Test for less than 10 ohm between the low reference circuit terminal 3 and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
3. Ignition ON, test for 4.8-5.2 V between the 5V reference circuit terminal 2 and ground.
• If less than the specified range, test the 5V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
• If greater than the specified range, test the 5V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
4. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
5. Test for greater than 500 kohm between the signal circuit terminal 1 and ground.
• If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the B37B Engine Oil Pressure Sensor.
6. Ignition ON, test for less than 0.3 V between the signal circuit terminal 1 and ground.
• If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the B37B Engine Oil Pressure Sensor.
7. If all circuits test normal, replace the K20 Engine Control Module.
8 Cylinder Engine RPO L99 or LS3
1. Ignition OFF, disconnect the harness connector at the B37B Engine Oil Pressure Sensor.
2. Test for less than 10 ohm between the low reference circuit terminal A and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
3. Ignition ON, test for 4.8-5.2 V between the 5V reference circuit terminal B and ground.
• If less than the specified range, test the 5V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
• If greater than the specified range, test the 5V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
4. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
5. Test for greater than 500 kohm between the signal circuit terminal C and ground.
• If less than the specified range, test the signal circuit terminal C for a short to ground. If the circuit tests normal, replace the B37B Engine Oil Pressure Sensor.
6. Ignition ON, test for less than 0.3 V between the signal circuit terminal C and ground.
• If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the B37B Engine Oil Pressure Sensor.
7. If all circuits test normal, replace the K20 Engine Control Module.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Engine Oil Pressure Sensor and/or Switch Replacement (Service and Repair) for LLT
* Engine Oil Pressure Sensor and/or Switch Replacement (Service and Repair) for L99 or LS3
* Control Module References (Programming and Relearning) for ECM replacement, setup and programming