The guys at OFI are awesome.
I've spent my share of time on that page.
At the ECM connector:
PIN 4
circuit K369
16ga BR/OR FUEL PRESSURE SOLENOID SUPPLY
PIN 52
circuit K370
16ga BR FUEL PRESSURE SOLENOID CONTROL
See page 8W - 80 - 98 for solenoid-end pinout. (per 2006 manual)
1. OPEN CIRCUITS
Turn the ignition off.
Disconnect the Fuel Pressure Solenoid harness connector.
Disconnect the ECM harness connectors.
Visually inspect the related wiring harness. Look for any chafed,
pierced, pinched, or partially broken wires. Repair as necessary.
Visually inspect the related wiring harness connectors. Look for broken,
bent, pushed out, or corroded terminals. Repair as necessary.
Measure the resistance of both Fuel Pressure Solenoid circuits between
the ECM harness connector and the Fuel Pressure Solenoid harness
connector.
Is the resistance below 10.0 ohms for both measurements?
Yes >> Go To 2
No >> Repair open circuit(s) as necessary.
2. FUEL PRESSURE SOLENOID RESISTANCE
Measure the resistance of the Fuel Pressure Solenoid.
Is the resistance between 3.5 and 5.5 ohms?
Yes >> Test Complete.
No >> Replace the Fuel Pressure Solenoid.
EDIT: Both the GM part and the Mopar part measured 3.8ohms for me.
3. CHECKING FOR AIR IN FUEL SYSTEM
Start the engine.
With the scan tool, compare the Fuel Pressure Setpoint with the Actual Fuel Pressure readings.
NOTE: If there is air in the fuel system, the Actual Fuel Pressure will oscillate more than 100 spi above
and/or below the Fuel Pressure Setpoint.
Does Actual Fuel Pressure oscillate more than 100 psi above and/or below the Fuel Pressure Setpoint?
Yes >> Refer to the Service Information to purge air from the fuel system.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No >> Go To 4
4. FUEL PRESSURE SOLENOID
With the scan tool, compare the Fuel Pressure Setpoint with the Actual Fuel Pressure readings.
NOTE: A sticking Fuel Pressure Solenoid is indicated by Actual Fuel Pressure gradually dropping below the
Fuel Pressure Setpoint then suddenly increasing (spiking) above the Fuel Pressure Setpoint.
Does Actual Fuel Pressure gradually decrease then suddenly increase (spike) above the Fuel Pressure
Yes >> Replace the Fuel Pressure Solenoid in accordance with the Service Information.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No >> Go To 5