This procedure covers the replacement of one or both knock sensors on the 2015-2020 Ford F-150 with the 3.5L EcoBoost V6 engine, which are located in the valley between the cylinder banks.

Warnings

Tools required

Parts

• Knock sensor (specify bank 1 or bank 2) × 1 — Motorcraft DY-1216 or equivalent
• Upper intake manifold gaskets × 1 — Use OEM specification
• Intake plenum cover gasket (if damaged) × 1 — Use OEM specification

Fluids

• Motorcraft Orange Coolant — 1 qt

Preparation

1. Ensure engine is completely cold to the touch
2. Disconnect negative battery cable and wait 5 minutes
3. Relieve fuel system pressure if any fuel line disconnection is necessary
4. Have replacement gaskets ready as reuse is not recommended
5. Clear codes and note which knock sensor bank has failed

Procedure

1. 1

   Remove engine cover and air intake
   Remove the plastic engine cover by pulling upward on the front edge to release the grommets. Disconnect the air intake tube from the throttle body by loosening the clamp and removing the breather hoses. Remove the air filter housing if necessary for access.
2. 2

   Disconnect electrical connectors
   Locate and disconnect all electrical connectors on top of the intake manifold including fuel injector harness connectors, throttle body connector, and any sensors mounted to the intake plenum. Press the release tabs and carefully pull connectors straight out. Label connections if needed for reassembly.
3. 3

   Remove charge air cooler outlet pipe
   Disconnect the charge air cooler (intercooler) outlet pipe from the throttle body and intake plenum. This pipe runs from the intercooler to the throttle body. Remove mounting bolts and carefully work the pipe free. Set aside with O-rings protected.
   ℹ️The charge air cooler pipe uses O-ring seals. Inspect and replace if damaged.
   Torque spec

   Mounting Bolts55 Nm (40 lb-ft)
4. 4

   Disconnect vacuum lines and PCV system
   Disconnect all vacuum lines attached to the intake manifold including brake booster line, purge valve line, and any other vacuum connections. Disconnect the PCV hose from the rear of the intake. Use a flathead screwdriver carefully if hoses are stuck.
5. 5

   Remove upper intake manifold bolts
   Remove the 10 bolts securing the upper intake manifold (plenum) to the lower intake manifold. Start from the outer bolts and work inward in a cross pattern. Keep bolts organized as they may be different lengths in different positions.
   ⚠Note bolt positions as some locations use different length bolts.
   Torque spec

   Gasket Bolts23 Nm (17 lb-ft)
6. 6

   Remove upper intake manifold
   Carefully lift the upper intake manifold assembly straight up and away from the engine. It may require gentle wiggling to break the gasket seal. Place on a clean work surface with the mating surface protected. Cover the lower intake ports with clean shop towels to prevent debris entry.
   ⚠️Immediately cover all open intake ports with clean towels. Any debris entering the engine will cause catastrophic damage.
7. 7

   Access knock sensors
   With the upper intake removed, the knock sensors are now visible in the valley between the cylinder banks. Bank 1 sensor is on the passenger side of the block, Bank 2 sensor is on the driver side. They are mounted to the engine block between the cylinders. Identify the failed sensor.
8. 8

   Disconnect knock sensor electrical connector
   Locate the electrical connector for the knock sensor being replaced. Press the release tab and carefully disconnect the connector. The connector may be difficult to access and require working from different angles with extensions.
9. 9

   Remove knock sensor
   Using a 12mm deep socket with appropriate extensions, carefully remove the knock sensor mounting bolt. The sensor location is tight and may require a wobble extension or universal joint. Once the bolt is removed, carefully extract the sensor from the block. Note the orientation.
   ⚠Do not drop the sensor bolt into the valley. Use magnetic socket if available.
   Torque spec

   Knock Sensor20 Nm (15 lb-ft)
10. 10

    Clean mounting surface
    Clean the knock sensor mounting surface on the engine block using a non-metallic brush or clean shop towel. Remove any old gasket material, corrosion, or debris. The surface must be clean and flat for proper sensor contact. Do not use metal brushes that could damage the aluminum.
    ⚠Ensure no debris falls into the engine valley or oil passages during cleaning.
11. 11

    Install new knock sensor
    Install the new knock sensor into the mounting hole in the correct orientation. Start the mounting bolt by hand to ensure proper thread engagement. Using a torque wrench, tighten the knock sensor to exactly 20 Nm (15 lb-ft). This torque is critical for proper sensor function.
    ⚠Knock sensor torque must be exact. Incorrect torque will cause false signals and engine performance problems.
    Torque spec

    Knock Sensor20 Nm (15 lb-ft)
12. 12

    Reconnect knock sensor connector
    Reconnect the electrical connector to the knock sensor. Ensure the connector clicks fully into place and the locking tab engages. Verify the connection is secure by gently pulling on the connector.
13. 13

    Prepare for intake manifold installation
    Remove the shop towels from the lower intake ports. Inspect the lower intake manifold mating surface and clean if necessary. Install new upper intake manifold gaskets onto the lower manifold, ensuring proper alignment with all port openings and bolt holes.
    ℹ️Do not reuse old intake gaskets. Always use new gaskets for proper seal.
14. 14

    Install upper intake manifold
    Carefully lower the upper intake manifold onto the lower manifold, aligning all gaskets and ensuring proper seating. Install all 10 bolts hand-tight first. Then torque bolts in a cross pattern from center outward to 23 Nm (17 lb-ft) to ensure even gasket compression and proper seal.
    Torque spec

    Gasket Bolts23 Nm (17 lb-ft)
15. 15

    Reinstall remaining components
    Reconnect all vacuum lines, PCV hose, and electrical connectors to their original positions. Install the charge air cooler outlet pipe with new O-rings if needed, torquing mounting bolts to specification. Reinstall the air intake system and engine cover. Reconnect the negative battery cable.
    Torque spec

    Mounting Bolts55 Nm (40 lb-ft)

Reassembly

1. Verify all electrical connections are fully seated and locked
2. Ensure no tools or parts were left in the engine valley
3. Check that all vacuum lines are properly connected
4. Verify charge air cooler pipe is secure with no air leaks possible

Verification

• Using an OBD-II scanner, clear all diagnostic trouble codes
• Start the engine and verify it runs smoothly without misfires or rough idle
• Allow engine to reach operating temperature and verify no coolant or vacuum leaks
• Perform a test drive and accelerate moderately to verify knock sensor is functioning
• Re-scan for codes after test drive to confirm knock sensor fault does not return
• Monitor for proper fuel trim and timing advance with scanner if available

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