Replace the camshaft position sensor on the 2016-2021 Honda Civic 1.5L turbo engine to restore proper engine timing signal and resolve related diagnostic trouble codes.

Warnings

Tools required

Parts

• Camshaft position sensor × 1 — 37840-RLF-003 or equivalent
• O-ring seal for sensor × 1 — Typically included with sensor

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool for at least 30 minutes
3. Open hood and secure with prop rod
4. Disconnect negative battery terminal and wait 3 minutes
5. Locate camshaft position sensor on rear of cylinder head near firewall (driver side of engine)

Procedure

1. 1

   Remove engine cover
   Grasp the engine cover firmly at the front corners and pull straight upward to release the four rubber grommets. Set the cover aside.
2. 2

   Access camshaft position sensor
   The camshaft position sensor is located on the rear of the cylinder head near the firewall, on the intake camshaft side. You may need to move aside wiring harnesses for better access. Use a flashlight to verify sensor location before proceeding.
3. 3

   Disconnect sensor electrical connector
   Press down on the locking tab of the electrical connector while pulling it away from the sensor. The connector may be tight due to seal compression. Use a small flathead screwdriver to gently pry the lock tab if necessary, being careful not to break the plastic housing.
4. 4

   Remove sensor mounting bolt
   Using a 10mm socket with extension, remove the single bolt securing the camshaft position sensor to the cylinder head. Keep this bolt as it will be reused if in good condition.
   Torque spec

   Camshaft Position Sensor10 Nm (7 lb-ft)
5. 5

   Extract old sensor
   Carefully pull the sensor straight out from the cylinder head. Use a gentle twisting motion if the sensor is stuck due to O-ring seal compression. Do not pry against the cylinder head surface. Inspect the old sensor for oil contamination, metal debris, or physical damage.
6. 6

   Clean sensor bore
   Wipe the sensor bore in the cylinder head with a clean shop towel. Remove any oil residue or debris. Inspect the bore for damage or scoring. A small amount of oil presence is normal, but excessive oil may indicate a leaking seal or internal engine issue.
7. 7

   Prepare new sensor
   Remove the new camshaft position sensor from packaging. Verify the new O-ring seal is properly seated in the sensor groove. Lightly coat the O-ring with clean engine oil to ease installation and prevent tearing. Do not use petroleum jelly or other lubricants.
8. 8

   Install new sensor
   Carefully insert the new sensor straight into the cylinder head bore. Push firmly until the sensor mounting flange is flush against the cylinder head surface. Ensure the sensor is fully seated before installing the bolt. The sensor should slide in with moderate resistance from the O-ring.
9. 9

   Torque sensor bolt
   Install the sensor mounting bolt and hand-tighten. Using a torque wrench, tighten the bolt to 10.0 Nm (7.0 lb-ft). Do not overtighten as this can crack the sensor housing or strip the threads in the aluminum cylinder head.
   Torque spec

   Camshaft Position Sensor10 Nm (7 lb-ft)
10. 10

    Reconnect electrical connector
    Push the electrical connector onto the sensor until you hear and feel a positive click. Gently tug on the connector to verify it is fully locked. Ensure the weather seal is properly seated to prevent moisture intrusion.
11. 11

    Reinstall engine cover
    Align the engine cover grommets with the posts on the valve cover and intake manifold. Press down firmly on all four corners until the cover snaps into place.
12. 12

    Reconnect battery and clear codes
    Reconnect the negative battery terminal. Using an OBD-II scanner, clear any stored camshaft position sensor diagnostic trouble codes (typically P0340, P0341, P0365, or P0366). Record any other codes present before clearing.

Reassembly

1. Ensure all electrical connections are secure and properly locked
2. Verify sensor mounting bolt is torqued to specification
3. Route wiring harnesses back to original positions to prevent contact with hot engine components

Verification

• Start the engine and verify it runs smoothly without misfires or rough idle
• Allow engine to idle for 2-3 minutes while monitoring for warning lights
• Use OBD-II scanner to verify no camshaft position sensor codes return
• Test drive vehicle and confirm normal acceleration and no check engine light
• Re-scan for codes after test drive to ensure repair is successful

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