Circuit Description
The engine oil pressure (EOP) sensor is mounted in the top rear of the engine. The EOP sensor measures changes in engine oil pressure. The EOP sensor has a 5-volt reference, a ground and a signal circuit. The EOP sensor changes resistance based on engine oil pressure and is used to determine when the oil pressure is below a certain threshold. When the oil pressure reaches a predetermined value, the powertrain control module (PCM) will determine this as high oil pressure. The PCM will then send a serial data message to the instrument panel (I/P) cluster to activate the Check Oil warning indicator. When the PCM senses a signal voltage higher than the normal operating range of the sensor, this DTC P0523 will set.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | The PCM detects that the EOP sensor signal circuit is greater than 4.9 volts. |
| • | The above condition is present for greater than 9 seconds. |
Action Taken When the DTC Sets
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM records the operating conditions at the time the diagnostic fails. |
| • | The PCM stores this information in the Failure Records. |
| • | The multifunction display (MFD) in the instrument cluster will display a message at key-on and key-off. |
Conditions for Clearing the DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC is cleared after 40 malfunction free warm-up cycles. |
| • | The PCM receives the 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 in determining how many miles since the DTC set. The Fail Counter and the Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail. |
| • | The PCM 5-volt reference circuits are internally connected within the PCM. If all the Engine Oil sensor circuits check to be OK, inspect related 5-volt reference circuits. Refer to DTC P0641 in Engine Controls - 5.7L. |
| • | If there is a failure with the Check Oil icon, more than likely it is an instrument cluster fault |
| • | Using the Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Failure Records data can aid in determining the distance travelled since the DTC reported a pass and/or fail. Operate the vehicle within the same Failure Records conditions (RPM, load, vehicle speed, temperature, etc.) that you observed. This will isolate when the DTC failed. |
| • | For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics Connector End View Reference: Engine Controls Connector End Views and Powertrain Control Module Connector End Views in Engine Controls - 5.7L and Instrument Cluster Schematics | ||||
1 | Did you perform the Instrument Cluster Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the Engine Oil Pressure Sensor parameter display greater than the specified value? | 4.5 V | Go to Step 3 | Go to Diagnostic Aids |
Does the Engine Oil Pressure Sensor parameter display less than the specified value? | 0.4 V | Go to Step 4 | Go to Step 5 | |
4 |
Is the resistance less than the specified value? | 5 ohms | Go to Step 7 | Go to Step 6 |
5 | Test the EOP sensor signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 8 |
6 |
Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 8 |
7 | Inspect for poor connections at the harness connector of the EOP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 |
8 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 |
9 | Replace the EOP sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical - 5.7L. Did you complete the replacement? | -- | Go to Step 11 | -- |
10 |
Important: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 5.7L. Did you complete the replacement? | -- | Go to Step 11 | -- |
11 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
