P0520 DTC Troubleshooting

Took the time to copy/edit this for another member and realized it was the wrong code... so im pasting it here in case anyone needs it:

P0520-ENGINE OIL PRESSURE SENSOR CIRCUIT
For the Engine System Schematic circuit diagram (Refer to 9 - ENGINE - SCHEMATICS AND DIAGRAMS).

² When Monitored:
Ignition on, engine not running.

² Set Condition:
The PCM senses the oil pressure is out of the calibrated range.

Possible Causes
(G6) ENGINE OIL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
RESISTANCE (G6) ENGINE OIL PRESSURE SENSOR SIGNAL CIRCUIT
(G6) ENGINE OIL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
RESISTANCE IN (F855) 5-VOLT SUPPLY CIRCUIT
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
ENGINE OIL PRESSURE SENSOR
PCM


Diagnostic Test
1. ACTIVE DTC
NOTE: Make sure that the engine oil is at the proper level. Also, check the customers oil change history to ensure that the oil is being changed at the correct intervals and that the proper oil viscosity is being used.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Yes >> Go To 2
No >> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.

2. (G6) ENGINE OIL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the C1 and C2 PCM harness connectors.
Disconnect the Engine Oil Pressure Sensor harness connector.
Ignition on, engine not running.
Measure the voltage on the (G6) Engine Oil Pressure Signal circuit in the Engine Oil Pressure Sensor harness connector.
Is the voltage above 0 volts?
Yes >> Repair the short to battery voltage in the (G6) Engine Oil Pressure Signal circuit.
No >> Go To 3

3. ENGINE OIL PRESSURE SENSOR
Turn the ignition off.
Connect the PCM harness connectors.
Ignition on, engine not running.
With a scan tool, monitor the Engine Oil Pressure Sensor voltage.
Connect a jumper wire between the (K900) Sensor Ground circuit and the (G6) Engine Oil Pressure Signal circuit.
NOTE: Engine Oil Pressure voltage should change from approximately 4.5 volts to less than 0.5 of a volt.
Is the voltage reading within the listed specification when the jumper wire is installed?
Yes >> Replace the Engine Oil Pressure Sensor.
No >> Go To 4
NOTE: Remove the jumper wire before continuing.

4. EXCESSIVE RESISTANCE IN THE (G6) ENGINE OIL PRESSURE SIGNAL CIRCUIT
Turn the ignition off.
Disconnect the C1 and C2 PCM harness connectors.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (G6) Engine Oil Pressure Signal circuit from the Engine Oil Pressure Sensor harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms for each circuit?
Yes >> Go To 5
No >> Repair the excessive resistance in the (G6) Engine Oil
Pressure Signal circuit.

5. (G6) ENGINE OIL PRESSURE SIGNAL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (G6) Engine Oil Pressure
Signal circuit Engine Oil Pressure Sensor harness connector.
Is the resistance below 100 ohms?
Yes >> Repair the short to ground in the (G6) Engine Oil Pressure Signal circuit.
No >> Go To 6

6. EXCESSIVE RESISTANCE IN THE (F855) 5–VOLT SUPPLY CIRCUIT
Measure the resistance of the (F855) 5-volt Supply circuit from the Engine Oil Pressure Sensor harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes >> Go To 7
No >> Repair the excessive resistance in the (F855) 5-volt Supply
circuit.

7. (F855) 5-VOLT SUPPLY SHORTED TO GROUND
Measure the resistance between ground and the (F855) 5-volt Supply circuit in the Engine Oil Pressure Sensor harness connector.
Is the resistance below 100 ohms?
Yes >> Repair the short to ground in the (F855) 5-volt Supply circuit.
No >> Go To 8

8. EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance of the (K900) Sensor Ground circuit from the Engine Oil Pressure Sensor harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes >> Go To 9
No >> Repair the excessive resistance in the (K900) Sensor
Ground circuit.

9. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes >> Repair as necessary.
No >> Replace and program the Powertrain Control Module per Service Information.