engine

Camshaft Position Sensor

for 2021 Honda Civic 1.5L I4 Turbo · FWD

Editorial review:Chris Hackleman — Master Technician · 20+ years · Jeff Moore — Master Mechanic · 20+ years

Difficulty

Easy

Time

1.0 h

Tools

Steps

✓Expert-verified. Personally reviewed and approved by OLP's master technicians (Chris Hackleman & Jeff Moore — 20+ years each). Always follow the vehicle's factory service information and torque specs.

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

⚠Allow engine to cool completely before starting work. Sensor is located near exhaust camshaft and can be extremely hot.

⚠Do not force the sensor during installation. Cross-threading the aluminum housing will require cylinder head repair.

ℹ️Disconnecting the battery will erase radio presets and may require power window reinitialization.

Tools required

10mm socket and ratchetEssential

Extension setEssential

Torque wrench (5-25 Nm range)Essential

Flathead screwdriver (small)

Electrical contact cleaner

Shop towelsEssential

OBD-II scannerEssential

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Parts

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

As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Preparation

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

Procedure

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
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
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
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
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
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
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
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
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
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
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
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

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