transmission

Neutral Safety Switch

for 2021 Honda Civic 1.5L I4 Turbo · FWD

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

Difficulty

Moderate

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.

This procedure covers the replacement of the neutral safety switch (also known as the shift position switch or inhibitor switch) on the CVT transmission of a 2016-2021 Honda Civic with the 1.5L turbo engine.

Warnings

⚠️Vehicle must be on level ground and properly supported on jack stands. Never work under a vehicle supported only by a floor jack.

⚠Perform this work with the engine and transmission cool to avoid burns from hot components and fluid.

⚠Only use genuine Honda DW-1 ATF. Incorrect transmission fluid can cause transmission damage.

ℹ️The neutral safety switch is located on the top side of the transmission case, accessible from above on this engine configuration.

Tools required

10mm socket and ratchetEssential

12mm socket and ratchetEssential

Torque wrenchEssential

Flathead screwdriver

Drain pan (4+ quart capacity)Essential

Shop towels or ragsEssential

Funnel for ATF refillEssential

Floor jack and jack standsEssential

Wheel chocksEssential

Parts

Neutral safety switch (shift position switch) × 1 — Use OEM specification
Switch O-ring seal × 1 — Usually included with new switch

Fluids

Honda DW-1 ATF — 2 qt

Preparation

Park vehicle on level ground and apply parking brake
Place wheel chocks behind rear wheels
Ensure transmission is in Park position
Allow engine and transmission to cool completely if recently driven
Disconnect negative battery cable and wait 3 minutes for airbag system discharge
Raise and support front of vehicle on jack stands if additional access is needed
Remove engine cover by pulling upward on clips

Procedure

1
Locate the neutral safety switch
The neutral safety switch is mounted on the top of the transmission case, toward the driver's side. It has an electrical connector and is secured by two bolts. Locate the switch assembly before proceeding.
2
Disconnect electrical connector
Press the tab on the electrical connector and carefully pull the connector away from the neutral safety switch. Do not pull on the wiring harness itself.
3
Position drain pan
Place a drain pan directly beneath the neutral safety switch location. When the switch is removed, a small amount of ATF (approximately 0.5-1 quart) will drain from the opening.
4
Remove switch mounting bolts
Using a 10mm socket, remove the two bolts securing the neutral safety switch to the transmission case. Keep these bolts as they will be reused unless damaged.
Torque spec
Mounting Bolts26 Nm (19 lb-ft)
5
Remove old switch
Carefully pull the neutral safety switch straight out from the transmission case. ATF will begin draining immediately. Allow fluid to drain into the pan. Remove and discard the old O-ring seal from the switch or transmission case opening.
6
Clean mounting surface
Use a clean shop towel to wipe the mounting surface on the transmission case clean of any debris, old seal material, or ATF residue. Ensure the mating surface is completely clean and dry before installing the new switch.
7
Install new O-ring seal
Install the new O-ring seal onto the new neutral safety switch. Lightly lubricate the O-ring with clean Honda DW-1 ATF to ease installation and prevent damage to the seal.
8
Install new switch
Align the new neutral safety switch with the shaft and mounting holes on the transmission case. The switch will only fit in one orientation. Push the switch firmly into place, ensuring it is fully seated against the transmission case.
9
Install and torque mounting bolts
Thread both mounting bolts by hand to prevent cross-threading. Using a torque wrench and 10mm socket, tighten the switch mounting bolts to 15.0 Nm (11.0 lb-ft) in a cross pattern to ensure even seating.
Torque spec
Mounting Bolts26 Nm (19 lb-ft)
10
Reconnect electrical connector
Firmly push the electrical connector onto the neutral safety switch until you hear and feel a positive click, indicating it is fully seated and locked.
11
Refill transmission fluid
Locate the transmission dipstick (yellow handle near the firewall). Remove the dipstick and insert a funnel. Add approximately 1.5-2.0 quarts of Honda DW-1 ATF to replace the fluid lost during switch replacement. Check the fluid level using the dipstick with the engine off and transmission in Park on level ground. The fluid should be between the lower and upper marks when cold.
12
Reinstall engine cover and lower vehicle
Reinstall the engine cover by aligning the clips and pressing down firmly. If the vehicle was raised, lower it from jack stands and remove wheel chocks. Reconnect the negative battery cable.

Reassembly

Ensure all electrical connectors are fully seated and locked
Verify no tools or rags were left in the engine compartment
Double-check that transmission fluid level is correct on the dipstick when cold

Verification

Start the engine and verify it only starts in Park and Neutral positions
With engine running and foot on brake, shift through all gear positions (P-R-N-D-S-L) and verify smooth shifting
Check that the gear position indicator on the instrument cluster matches the shifter position in all gears
Verify reverse lights illuminate when transmission is shifted into Reverse
Check for any ATF leaks around the neutral safety switch after running the engine for 2-3 minutes
Test drive the vehicle to confirm normal transmission operation and no warning lights on the dashboard
Recheck transmission fluid level after test drive with engine at operating temperature, running in Park on level ground

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