For a complete wiring diagram Refer to Section 8WThe Fuel Pressure Solenoid (FPS) is a solenoid operated valve designed to regulate fuel pressure in the fuel rail. The FPS valve is positioned in the in-line with the outlet passage of the high pressure fuel rail. The solenoid receives 12 volt power and a duty-cycle ground signal from the ECM. When the solenoid is not actuated (no ground signal from the ECM), the fuel rail outlet passage opens allowing fuel pressure in the rail to escape into the return circuit to the fuel tank. When the ECM grounds the FPS control signal, the solenoid valve closes allowing fuel pressure to build in the rail.When Monitored:With the ignition on and the Fuel Pressure Solenoid command off.Set Condition:The ECM detects that the (K370) Fuel Pressure Solenoid Control circuit is open for 0.28 second.Possible CausesINTERMITTENT DTC(K370) FUEL PRESSURE SOLENOID CONTROL CIRCUIT SHORTED TO GROUND(K370) FUEL PRESSURE SOLENOID CONTROL CIRCUIT OPEN OR HIGH RESISTANCE(K369) FUEL PRESSURE SOLENOID 12 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCEFUEL PRESSURE SOLENOIDENGINE CONTROL MODULE (ECM)Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)1. DTC IS ACTIVEIgnition on, engine not running.With the scan tool, Clear DTCs in the Engine Control Module (ECM).With the scan tool, actuate the Fuel Pressure Solenoid at 100%.Monitor the scan tool for at least two minutes.With the scan tool, select View DTCs.Is the status Active for this DTC?YesGo To 2 NoRefer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)2. (K370) FUEL PRESSURE SOLENOID CONTROL CIRCUIT SHORTED TO GROUND

Turn the ignition off.Disconnect the Fuel Pressure Solenoid harness connector.Disconnect the Engine Control Module (ECM) harness connector.Measure the resistance between ground and the (K370) Fuel Pressure Solenoid Control circuit in the Fuel Pressure Solenoid harness connector.Is the resistance above 1000 ohms?YesGo to 3NoRepair the (K370) Fuel Pressure Solenoid Control circuit for a short to ground.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)3. (K370) FUEL PRESSURE SOLENOID CONTROL CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K370) Fuel Pressure Solenoid Control circuit between the Fuel Pressure Solenoid harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms?YesGo to 4NoRepair the (K370) Fuel Pressure Solenoid Control circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)4. (K369) FUEL PRESSURE SOLENOID 12 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K369) Fuel Pressure Solenoid 12 Volt Supply circuit between the Fuel Pressure Solenoid harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms?YesGo to 5NoRepair the (K369) Fuel Pressure Solenoid 12 Volt Supply circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)5. FUEL PRESSURE SOLENOID

Connect the Engine Control Module (ECM) harness connector.Turn the ignition on.With the scan tool, actuate the Fuel Pressure Solenoid (Rail Pressure Actuator) to 100%.Using a 12 volt test light connected to 12 volts, check the (K370) Fuel Pressure Solenoid Control circuit in the Fuel Pressure Solenoid harness connector.The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.The circuit will remain actuated by the controller for 30 seconds. Be certain the actuation is active when checking the circuit.Is the test light illuminated and bright with the actuation at 100%?YesReplace the Fuel Pressure Solenoid in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 66. ENGINE CONTROL MODULE (ECM)Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Fuel Pressure Solenoid and the Engine Control Module (ECM).Look for any chafed, pierced, pinched, or partially broken wires.Look for broken, bent, pushed out or corroded terminals.Refer to any Technical Service Bulletins that may apply.Were any problems found?YesRepair as necessary.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace the Engine Control Module (ECM) in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)