Transmission Range Sensor

Replace the transmission range sensor (also called inhibitor switch or neutral safety switch) on a CVT-equipped 2016-2021 Honda Civic 1.5T to restore proper gear position detection and starting functionality.

Warnings

Tools required

Parts

• Transmission range sensor × 1 — Honda 28900-P7W-003 or equivalent
• Transmission range sensor O-ring × 1 — Usually included with sensor

Fluids

• Honda DW-1 ATF — 1 qt

Preparation

1. Park vehicle on level ground and apply parking brake firmly
2. Place wheel chocks behind rear wheels
3. Disconnect negative battery cable and wait 3 minutes before proceeding
4. Raise and support front of vehicle on jack stands at proper lift points
5. Remove driver side front wheel for improved access
6. Remove plastic splash shield or undertray from driver side using 10mm fasteners

Procedure

1. 1

   Locate the transmission range sensor
   The transmission range sensor is mounted on the left (driver) side of the CVT transmission case, near the shift cable connection. It is a black electrical component with a 6-pin connector and secured by two bolts. Position your drain pan below the sensor area as some ATF will leak when removed.
2. 2

   Disconnect the electrical connector
   Press the lock tab on the 6-pin electrical connector and carefully pull it straight away from the sensor. Do not pull on the wires themselves. Inspect the connector for corrosion or damage.
3. 3

   Remove the sensor mounting bolts
   Remove the two 10mm sensor mounting bolts. Keep these bolts as they will be reused. Note the orientation of the sensor before removal - the electrical connector should face toward the front of the vehicle.
4. 4

   Remove the old sensor
   Carefully pull the sensor straight out from the transmission case. ATF will drain from the opening - this is normal. Allow it to drain into your pan. Remove and discard the old O-ring from the sensor or transmission case.
5. 5

   Clean the mounting surface
   Use a clean shop towel to wipe the transmission case mounting surface clean of any old ATF, debris, or remnants of the old O-ring. Do not allow dirt to enter the transmission opening. Inspect the transmission bore for damage.
6. 6

   Prepare the new sensor
   Install the new O-ring onto the new sensor. Lightly coat the O-ring with clean Honda DW-1 ATF to aid installation and prevent damage. Do not use petroleum-based lubricants.
7. 7

   Install the new sensor
   Align the sensor with the mounting holes and the internal shaft. The sensor will only install in one orientation - the electrical connector should face forward. Push the sensor firmly into place until it seats fully against the transmission case. Do not force it; if it doesn't go in easily, check the alignment.
8. 8

   Install and torque the mounting bolts
   Install both 10mm sensor mounting bolts and hand-tighten them. Using a torque wrench, tighten both bolts to 10.0 Nm (8.0 lb-ft) in a cross pattern to ensure even seating.
9. 9

   Reconnect the electrical connector
   Push the 6-pin electrical connector onto the sensor until you hear and feel a positive click. Gently tug on the connector to verify it is fully locked in place.
10. 10

    Check and top off ATF level
    With the vehicle still raised and level, locate the transmission dipstick (yellow handle) near the firewall. Check the ATF level and add Honda DW-1 ATF as needed to replace what was lost during sensor removal. Typical loss is 0.5-1.0 quart. Check level with engine cold.
11. 11

    Reinstall undertray and wheel
    Reinstall the plastic splash shield or undertray using the 10mm fasteners. Reinstall the driver side front wheel and torque lug nuts to Honda specification (108 Nm / 80 lb-ft) in a star pattern.

Reassembly

1. Reconnect the negative battery cable
2. Lower the vehicle from jack stands
3. Do not start the engine until you have verified proper ATF level

Verification

• Turn ignition to ON position (do not start engine) - verify no warning lights are illuminated on the dash
• With foot firmly on brake, verify the engine will only start in Park or Neutral positions
• Verify the gear position indicator on the dash matches the actual shifter position in all gear selections (P, R, N, D, S, L)
• Start the engine and verify smooth shifting through all gear ranges
• Check for ATF leaks around the sensor after running the engine to operating temperature
• Use a Honda scan tool or compatible OBD-II scanner to verify no transmission range sensor DTCs are present
• Test drive the vehicle and confirm normal CVT operation and proper shift lock function

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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