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TexZ71

By TexZ71
in Ask A GM Technician

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TexZ71 Enthusiast

TexZ71

Posted
Posted

3 weeks ago I had a oil pressure sensor error... Long story short I was 4 quarts low on oil. I brushed it off and placed blame on the dealership. Fast Forward three weeks and I'm driving to work with zero oil pressure on the gauge. I thought it was the gauge since I got no movement with the key in acc power. I decided to check the dipstick even tho I knew it was just filled less than a month ago... Low and behold the freaking oil is dry again and not even registering on the dipstick. I'm lost because I've checked for leaks and haven't found anything... PLS HELP.

 

2008 1500, 5.3L, crew, z71, 100,000mi, city/hwy driving

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

If it is going through that much oil you should be able to see it out the exhaust. Going by your miles on truck, and how many years old it is, 3 weeks is like 1200 miles. it should be pretty blue out the exhaust.

TexZ71 Enthusiast

TexZ71

Posted
  • Author
Posted

***Update*** put 2 quarts in and the oil pressure gauge is still at zero. I got a high voltage error code to the oil pressure sensor.

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

Where do you see "high voltage error"? What does the oil level look like now? If you have zero oil pressure, you would hear it on start up, within 10 to 15 seconds. First noise would be lifter noise. If you get that, shut the truck off. Although I would think that if you got the zero oil pressure while driving on the highway, there is already damage done.

I have an SL so no oil pressure gauge. I have the light on the dash that I think is more for oil level than pressure. I may be wrong, the light may be for pressure. Does your truck have the light as well as the gauge? If so, is that light on?

TexZ71 Enthusiast

TexZ71

Posted
  • Author
Posted

The engine threw the code to the diagnostics machine I have... Oil level still good.

No knocking.

Only has the gauge- no light.

Engine light was the only thing that came on when it had the code.

 

IM JUST GONNA START WITH THE OIL PRESSURE SENSOR, wires, and then the oil pump.

TexZ71 Enthusiast

TexZ71

Posted
  • Author
Posted

Update- I ended up removing the oil pressure switch and replacing it with a manual oil pressure gauge. I needed to know that the engine still had oil pressure because the dash gauge was on zero. So that eliminates the worst fear for me which was a internal issue or oil pump.

 

Next- testing the oil pressure switch with I jumper box and a test light.

 

Then if that checks out... Dash gauge, and wiring

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

Update- I ended up removing the oil pressure switch and replacing it with a manual oil pressure gauge. I needed to know that the engine still had oil pressure because the dash gauge was on zero. So that eliminates the worst fear for me which was a internal issue or oil pump.

 

Next- testing the oil pressure switch with I jumper box and a test light.

 

Then if that checks out... Dash gauge, and wiring

 

You don't actually say you have oil pressure with the manual gauge installed, but you do infer it. Was oil pressure something over 10psi at idle?

Since you have the oil pressure sender removed, why not put a new one back in? I have no idea what they cost, but, if they are not real pricey I would replace it since it is out. I am old, and don't know how the newer systems are, but, in my day, oil pressure senders were basically a variable ground. In other words, you could short the wire to ground and you would get max oil pressure on the gauge. Two wire sensors required a resistor between the two wires to get the gauge to read something. Connecting the two wires together would give the opposite reading of the two wires not connected together. So, not connected may show 0psi, connected together would show max oil pressure. Some cars were the opposite, and open connection was max oil pressure, shorted together was 0psi.

gmtech4 Senior Enthusiast

gmtech4

Posted
Posted

the easy way is following this trouble chart ,,,,understanding how the computer controlled oil pressure gauge works,,,,i agree,replace the sender and try it

 


DTC P0521, P0522, or P0523






Diagnostic Instructions
DTC Descriptors DTC P0521

Engine Oil Pressure (EOP) Sensor Performance

DTC P0522

Engine Oil Pressure (EOP) Sensor Circuit Low Voltage.

DTC P0523

Engine Oil Pressure (EOP) Sensor Circuit High Voltage


Diagnostic Fault Information

















































Circuit


Short to Ground


High Resistance


Open


Short to Voltage


Signal Performance


Engine Oil Pressure 5 V Reference


P0522


1


P0522


P0523


P0521


Engine Oil Pressure Sensor Signal


P0522


1


P0522


P0523


P0521


Low Reference


—


1


P0523


—


P0521


1. Engine Oil Pressure Indicator Malfunction


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 V reference circuit. The engine control module (ECM) supplies 5 V
to the EOP sensor via the 5 V reference circuit and provides ground via the EOP low
reference circuit. The ECM monitors the signal circuit of the EOP sensor to
determine the EOP sensor voltage is within the normal operating range of approximately
1–4 V. 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
via the serial data circuit to the body control module (BCM). The BCM then sends the
EOP information
to the instrument panel cluster (IPC) via the serial data circuit.


Conditions for Running the DTC

The engine is running.


Conditions for Setting the DTC
P0521
  • 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).
  • The engine oil pressure is outside of a calculated working range determined by engine
    speed and temperature.

P0522
  • The ECM detects that the EOP sensor signal circuit is less than 0.1 V.
  • The above condition is present for greater than 10 seconds.

P0523
  • The ECM detects that the EOP sensor signal circuit is greater than 4.4 V.
  • 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.

Diagnostic Aids

DTC P0521 can set if engine oil pressure is outside the calculated engine oil pressure
model stored in the engine control module. This can be an indication of mechanical
engine issues causing lower than expected engine oil pressure.


Reference Information
Schematic Reference


Instrument Cluster Schematics


Connector End View Reference


Component Connector End Views


Description and Operation


Instrument Cluster Description and Operation


Electrical Information Reference
Scan Tool Reference


Control Module References
for scan tool information


Circuit/System Verification
  1. Engine running, observe the scan tool Engine Oil Pressure Sensor parameter. The reading
    should be between 41–448 kPa (6–65 psi).
  2. Verify the engine oil pressure, refer to:

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the engine oil pressure (EOP) sensor.
  2. Ignition OFF, test for less than 1.0 Ω between the low reference circuit terminal
    listed below and ground:
    • Low Reference Terminal 3 (Gas)
    • Low Reference Terminal 1 (Diesel)
    • 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 5 V reference circuit terminal listed
    below and ground:
    • 5 V Reference Terminal 2 (Gas)
    • 5 V Reference Terminal 3 (Diesel)
    • If less than the specified range, test the 5 V 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 5 V reference circuit for a short to
      voltage. If the circuit tests normal, replace the K20 Engine Control Module.
  4. Verify the scan tool Engine Oil Pressure Sensor parameter is less than 8 kPa (1.2 psi).
    • If greater than the specified range, test the signal circuit terminal listed below
      for a short to voltage or an open/high resistance. If the circuit tests normal, replace
      the K20 Engine Control Module.
    • Signal Terminal 1 (4.8L, 5.3L or 6.0L Gas)
    • Signal Terminal 2 (6.6L Diesel)
    • Signal Terminal 3 (4.3L Gas)
  5. Install a 3A fused jumper wire between the signal circuit terminal and the 5 V reference
    circuit terminal listed below. Verify the scan tool Engine Oil Pressure Sensor parameter
    is greater than 550 kPa (80 psi).
    • Signal Terminal 1 (4.8L, 5.3L or 6.0L Gas)
    • Signal Terminal 2 (6.6L Diesel)
    • Signal Terminal 3 (4.3L Gas)
    • 5 V Reference Terminal 2 (Gas)
    • 5 V Reference Terminal 3 (Diesel)
    • If less than the specified range, test the signal circuit for a short to ground or
      an open/high resistance. If the circuit tests normal, replace the K20 Engine Control
      Module.
  6. If all circuits test normal, test or replace the EOP sensor.

Repair Instructions

Perform the
Diagnostic Repair Verification
after completing the repair.


  • 2 months later...
TexZ71 Enthusiast

TexZ71

Posted
  • Author
Posted

FYI- issue was the oil pressure switch

 

Turned off the AFM and that fixed the oil consumption problem

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