Diagnostic Instructions
DTC Descriptor
DTC P0523: Engine Oil Pressure (EOP) Sensor Circuit High Voltage.
Diagnostic Fault Information
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. The IPC illuminates the engine oil pressure indicator when it receives a GMLAN serial data message indicating a low engine oil
pressure condition.
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
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Scan Tool Data List
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the engine oil pressure (EOP) sensor.
- Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit and ground.
| ⇒ | If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the engine control module (ECM). |
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and ground.
| ⇒ | If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
- Install a 3A fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool Engine Oil Pressure Sensor parameter is less than 4.8 volts or 880 kPa (127.6 psi).
| ⇒ | If greater than 4.8 volts or 880 kPa (127.6 psi), test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
- If all circuits test normal, test or replace the EOP sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
