Remove and replace the fuel pressure regulator on the CP3 high-pressure fuel pump to restore proper fuel system pressure control.

Warnings

Tools required

Parts

• Fuel pressure regulator × 1 — Use OEM Mopar or Bosch specification
• Fuel pressure regulator O-ring kit × 1 — Usually included with regulator
• Shop towels × 1 — Standard

Preparation

1. Ensure engine has been off for minimum 2 hours to allow fuel pressure to bleed down
2. Park vehicle on level surface and engage parking brake
3. Disconnect both negative battery cables to prevent accidental starting
4. Remove engine cover by pulling upward on front edge and lifting off mounting grommets
5. Clean entire area around CP3 fuel pump and fuel pressure regulator with parts cleaner to prevent contamination
6. Place drain pan under work area to catch fuel spillage

Procedure

1. 1

   Access the fuel pressure regulator
   Locate the fuel pressure regulator on the rear of the CP3 high-pressure fuel pump on the driver side of the engine. The regulator is a cylindrical component with an electrical connector and return fuel line. Remove any air intake components or hoses obstructing access if necessary.
2. 2

   Disconnect electrical connector
   Press the red safety tab on the fuel pressure regulator electrical connector and pull connector straight off the regulator. Move connector aside and secure away from work area.
3. 3

   Disconnect fuel return line
   Using appropriate fuel line disconnect tool, disconnect the fuel return line from the top of the pressure regulator. Be prepared for residual fuel spillage. Allow fuel to drain into pan, then cap or plug the line to prevent contamination.
   ⚠Residual fuel under pressure may spray when line is disconnected. Wear safety glasses and have towels ready.
   Torque spec

   Fuel Line25 Nm (18 lb-ft)
4. 4

   Remove regulator mounting screws
   Using T25 Torx driver, remove the two regulator mounting screws securing the fuel pressure regulator to the CP3 pump body. Keep screws in clean location for reinstallation.
   Torque spec

   Regulator Mounting Screws5 Nm (4 lb-ft)
5. 5

   Remove fuel pressure regulator
   Carefully pull the fuel pressure regulator straight out from the pump body. The regulator has an O-ring seal that may require slight twisting motion to break free. More residual fuel will drain from the pump cavity - catch with towels.
6. 6

   Clean mounting surface
   Thoroughly clean the regulator mounting bore in the CP3 pump body using clean shop towels. Inspect for any debris, metal particles, or damage. Remove the old O-ring from the groove if it remained in the pump body. The mounting surface must be completely clean and dry.
   ⚠Any contamination entering the high-pressure pump can cause immediate failure. Ensure absolute cleanliness.
7. 7

   Prepare new regulator
   Remove new fuel pressure regulator from packaging. Verify new O-ring is properly seated in the groove on the regulator body. Lightly lubricate O-ring with clean diesel fuel - do not use petroleum jelly or other lubricants.
8. 8

   Install new fuel pressure regulator
   Carefully insert the new fuel pressure regulator straight into the pump body bore, ensuring O-ring does not roll or pinch. Push regulator fully into position until it seats against the pump housing.
9. 9

   Install mounting screws
   Thread both T25 Torx mounting screws by hand to prevent cross-threading. Tighten screws in alternating pattern (one turn each) to seat regulator evenly. Final torque both screws to specification using torque wrench.
   Torque spec

   Regulator Mounting Screws5 Nm (4 lb-ft)
10. 10

    Reconnect fuel return line
    Remove cap or plug from fuel return line. Inspect line end and O-ring for damage. Push fuel line firmly onto regulator fitting until it clicks into place. Tug on line to verify secure connection.
    Torque spec

    Fuel Line25 Nm (18 lb-ft)
11. 11

    Reconnect electrical connector
    Push electrical connector straight onto fuel pressure regulator until it clicks. Verify red safety tab locks into place. Tug gently on connector to confirm secure connection.
12. 12

    Final inspection and cleanup
    Inspect all connections for proper seating. Clean any spilled fuel from engine components and surrounding area. Reinstall any air intake components that were removed. Reinstall engine cover.

Reassembly

1. Reconnect both negative battery cables
2. Prime fuel system by cycling ignition key to ON position (without cranking) 3-4 times for 10 seconds each
3. Start engine and inspect for fuel leaks around regulator and return line connection
4. Allow engine to idle for 5 minutes while monitoring for leaks or unusual operation

Verification

• Verify no fuel leaks at regulator body, mounting area, or return line connection
• Check that engine starts normally without extended cranking
• Verify no fuel pressure related diagnostic codes are present using scan tool
• Confirm engine idles smoothly without surging or rough running
• Test drive vehicle to verify normal power delivery and no fuel pressure warnings

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