Replace the coolant temperature sensor on the 2018-2024 Honda Accord 1.5L Turbo engine to restore accurate temperature readings and proper engine management.

Warnings

Tools required

Parts

• Engine coolant temperature sensor × 1 — Use OEM specification
• O-ring for coolant temperature sensor × 1 — Usually included with sensor

Fluids

• Honda Type 2 Coolant (Blue) — 1 qt

Preparation

1. Ensure engine is completely cool to the touch
2. Position vehicle on level ground and engage parking brake
3. Open hood and locate coolant temperature sensor on thermostat housing (driver side of engine)
4. Place drain pan under engine to catch coolant

Procedure

1. 1

   Partially drain cooling system
   Remove the radiator cap slowly to release any residual pressure. Locate the coolant drain plug on the lower radiator tank (driver side). Place drain pan underneath and loosen the drain plug to drain approximately 1-2 quarts of coolant, just enough to bring the coolant level below the sensor location. Close drain plug when level is sufficient.
   Torque spec

   Coolant Drain Plug15 Nm (11 lb-ft)
2. 2

   Disconnect sensor electrical connector
   Locate the coolant temperature sensor on the thermostat housing near the front of the engine. Press the release tab on the electrical connector and carefully pull the connector away from the sensor. If the connector is tight, use a small flathead screwdriver to assist with the release tab.
3. 3

   Remove coolant temperature sensor
   Using a 19mm deep socket and ratchet, carefully turn the sensor counterclockwise to remove it from the thermostat housing. Be prepared for a small amount of coolant to leak from the opening. Remove the sensor completely and have a shop towel ready to catch any drips.
4. 4

   Inspect and clean sensor port
   Examine the sensor port in the thermostat housing for debris or corrosion. Wipe the sealing surface clean with a shop towel. Inspect the old sensor and verify the O-ring came out with the sensor. If the O-ring remained in the housing, carefully extract it with a small pick or screwdriver.
5. 5

   Install new coolant temperature sensor
   Verify the new sensor has a fresh O-ring installed. Carefully thread the new sensor into the thermostat housing by hand to ensure proper alignment and prevent cross-threading. Once hand-tight, use the 19mm socket and ratchet to snug the sensor. Tighten to approximately 15-20 Nm (11-15 lb-ft) - firm but do not overtighten as this can damage the plastic housing.
6. 6

   Reconnect electrical connector
   Push the electrical connector onto the new sensor until you hear and feel a positive click. Gently tug on the connector to verify it is securely locked in place.
7. 7

   Refill cooling system
   Using a funnel, add Honda Type 2 (blue) coolant to the radiator until the level reaches the base of the filler neck. Start the engine and allow it to warm up to operating temperature with the radiator cap off. As the thermostat opens, the coolant level will drop. Add additional coolant as needed to maintain proper level. Watch for leaks around the sensor.
8. 8

   Bleed cooling system
   With engine at operating temperature, rev the engine to 3000 RPM several times to help purge air from the system. Top off coolant level as needed. Install the radiator cap securely. Check the coolant reservoir and fill to the MAX line if necessary.

Reassembly

1. Ensure all electrical connections are secure and properly seated
2. Verify radiator cap is installed and tight
3. Check coolant reservoir level is at MAX line
4. Wipe up any spilled coolant from engine surfaces

Verification

• Start the engine and verify the temperature gauge operates normally and reaches normal operating temperature
• Use a scan tool to verify the coolant temperature sensor reads accurately (approximately 190-200°F at operating temperature)
• Inspect the sensor area for any coolant leaks after the engine reaches operating temperature
• Check for diagnostic trouble codes (DTCs) and verify no temperature-related codes are present
• Allow engine to cool and recheck coolant level in reservoir, top off if needed

More procedures for this vehicle