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Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: Chevy
Satisfied Customers: 2042
Experience:  Owner at Carolina Auto Service & Sales , 20 years Experience in Foreign & Domestic vehicles A6 - Electrical / Electronic systems A7 Heating / Air Conditioning systems
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I have a 2010 Chevy Tahoe. The other day my wife was driving

Customer Question

I have a 2010 Chevy Tahoe. The other day my wife was driving it the oil pressure suddenly dropped. The dash said stop engine now. So she stopped and called me. I went and started it and it had 40 lbs oil pressure. I drove it about an hour and it the oil pressure started to drop again. I stopped and put my scanner on it and it had the following code: P0521 oil pressure sensor range. I don't know if it is the sensor, pump or strainer. Has anyone encountered this before?
Submitted: 19 days ago.
Category: Chevy
Expert:  Chad Farhat replied 19 days ago.

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Expert:  Chad Farhat replied 19 days ago.

hey how are you

DTC P0521 (5.3L Engine) Diagnostic Instructions * Perform the Diagnostic System Check - Vehicle ( See: Vehicle > Initial Inspection and Diagnostic Overview > Diagnostic System Check - Vehicle) prior to using this diagnostic procedure. * Review Strategy Based Diagnosis ( See: Vehicle > Initial Inspection and Diagnostic Overview > Strategy Based Diagnosis) for an overview of the diagnostic approach. * Diagnostic Procedure Instructions ( See: Vehicle > Initial Inspection and Diagnostic Overview > Diagnostic Procedure Instructions) provides an overview of each diagnostic category. DTC Descriptor DTC P0521 - Engine Oil Pressure (EOP) Sensor Performance Diagnostic Fault Information

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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 if the EOP 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 a serial data message. The ECM can also predict oil pressure as a function of engine speed and engine temperature.

Conditions for Running the DTC

* The engine is running with engine speed between 700-3,500 RPM.
* Oil temperature is less than 150°C (302°F).
* Engine load stability is less than 250 kPa (36.2 psi).
* Engine predicted pressure is between 50 kPa (7.3 psi) and 400 kPa (58 psi).
* No crank sensor DTCs set.
* No coolant sensor DTCs set.
* No intake air temperature sensor DTCs set.
* No MAF DTCs set.
* No oil pressure sensor circuit DTCs set.

Conditions for Setting the DTC

The ECM detects that the difference between the predicted oil pressure and the actual oil pressure is either less than 47 kPa (6.8 psi) or greater than 50 kPa (7.3 psi).

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.

Reference Information
Schematic Reference

Instrument Cluster Schematics ( See: Instrument Panel, Gauges and Warning Indicators > Electrical > Instrument Cluster Schematics)
Connector End View Reference

Component Connector End Views ( See: Vehicle > Connector Views)
Description and Operation

* Instrument Cluster Description and Operation ( See: Instrument Panel, Gauges and Warning Indicators > Components > Instrument Cluster)
* Indicator/Warning Message Description and Operation ( See: Instrument Panel, Gauges and Warning Indicators > Components > Indicator/Warning Message)

Electrical Information Reference

* Circuit Testing ( See: Vehicle > Component Tests and General Diagnostics > Circuit Testing)
* Connector Repairs ( See: Vehicle > Component Tests and General Diagnostics > Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections ( See: Vehicle > Component Tests and General Diagnostics > Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs ( See: Vehicle > Component Tests and General Diagnostics > Wiring Repairs)

Scan Tool Reference

Control Module References ( See: Vehicle > Programming and Relearning) for scan tool information.

Circuit/System Verification

Engine ON, observe the Engine Oil Pressure Sensor parameter. The reading should be between 41-448 kPa (6-65 psi).

Circuit/System Testing

1. Engine ON, transmission in park, vary the engine speed by 500 RPM.
2. Verify the scan tool Engine Oil Pressure Sensor parameter changes by more than 34.5 kPa (5 psi).

◊If less than 34.5 kPa (5 psi), refer to Oil Pressure Diagnosis and Testing ( See: Engine > Component Tests and General Diagnostics > Oil Pressure Diagnosis and Testing).

3. If the pressure tests normal, replace the EOP sensor.

Repair Instructions

Perform the Diagnostic Repair Verification ( See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > Diagnostic Repair Verification) after completing the diagnostic procedure.

Engine Oil Pressure Sensor and/or Switch Replacement ( See: Oil Pressure Sensor > Removal and Replacement).

Expert:  Chad Farhat replied 19 days ago.

The oil pressure switch is a common failure on them,but check the oil pressure is good first ,it needs to have an oil pressure gauge hooked up

Please let me know if you need anything else on it, just reply back and we will continue

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you can always come back to this conversation and ask me any follow up question you may have on this issue

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Thank You
Chad Farhat
ASE Certified Technician

Customer: replied 19 days ago.
thanks
Expert:  Chad Farhat replied 19 days ago.

You are very welcome

Hope I was helpful to you

A 5 Star Positive Rating is Much Appreciated

This Post Will Stay Open for You To Come back and Ask me Any Follow Up Question You May have on this issue , even after you rate me

Thank You

Chad Farhat
ASE Certified Tedchnician

Expert:  Chad Farhat replied 17 days ago.

Please let me know if you need anything else on it, just reply back and we will continue

If you are good, Please Kindly Rate Me.

A 5 Star Rating is much Appreciated

If you feel I have not been helpful Please DO NOT RATE ME BAD OR POOR (1 or 2 stars) ,You can always ask me again or I can opt out of your question & open it for another expert ,that will provide you with more or better assistance on this issue

Please keep in mind that when you rate me , it does not end our conversation.

you can always come back to this conversation and ask me any follow up question you may have on this issue

(you can copy this link page & paste it in your browser when ready and it will open up our conversation again)

Thank You
Chad Farhat
ASE Certified Technician