DTC Descriptor
DTC P0523: Engine Oil Pressure (EOP) Sensor Circuit High Voltage.Diagnostic Fault Information
Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Engine Oil Pressure 5-volt Reference Circuit | P0522 | P0522 | -- | P0521 |
Engine Oil Pressure Sensor Signal Circuit | P0522 | P0522 | P0523 | P0521 |
Low Reference | -- | P0523 | -- | P0521 |
Circuit/System Description
The engine oil pressure (EOP) sensor changes voltage based on the engine oil pressure. The EOP sensor is a 3-wire sensor comprising of the signal circuit, the low reference circuit and the 5-volt reference circuit. The engine control module (ECM) supplies 5 volts to the EOP sensor via the 5-volt reference circuit and provides ground via the EOP low reference circuit. The ECM monitors the signal circuit of the EOP sensor to determine the engine oil pressure sensor voltage is within the normal operating range of approximately 1-4 volts. When the engine oil pressure is high, the EOP sensor voltage is high and the ECM senses a high signal voltage. When the engine oil pressure is low, the EOP 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 GMLAN serial data message.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | The ECM detects that the EOP sensor signal circuit is greater than 4.8 volts. |
| • | The above condition is present for greater than 10 seconds. |
Action Taken When the DTC Sets
| • | The ECM records the operating conditions at the time the diagnostics 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. |
Reference Information
Schematic Reference
| • | Engine Controls Schematics for the 3.9L engine |
Connector End View Reference
| • | Engine Control Module Connector End Views for the 3.9L engine |
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- With the ignition OFF, disconnect the EOP sensor.
- With the ignition ON, install a scan tool and observe the Engine Oil Pressure Sensor parameter in the IPC ECM Data List.
- With the ignition OFF, disconnect the negative battery cable and measure the resistance of the EOP sensor low reference circuit.
| ⇒ | If the EOP sensor parameter is at or above 8 kPa (1.16 psi), check the EOP sensor signal circuit for a short to voltage. |
| ⇒ | If the resistance measured is greater than 5 ohms, check the EOP sensor low reference circuit for an open or a high resistance. |
| ⇒ | If the resistance measured is less than 5 ohms, replace the EOP sensor. |
| ⇒ | If both circuits tests normal, replace the ECM. |
Repair Instructions
Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Engine Oil Pressure Sensor and/or Switch Replacement for the 3.9L engine |
| • | Control Module References for ECM replacement, setup and programming |
