The knock sensor (KS) is part of the engine's detonation-detection system. For the 2015 Civic, the KS is mounted directly to the engine block and wired to the engine control unit (ECU). In practice, you’ll typically find it on the side of the cylinder block near the cylinder head, with the connector running toward the back of the engine bay. The exact spot can vary by engine option, but the KS is always mounted to the engine rather than on the intake manifold or external brackets.
Where to look on the 2015 Civic
The 2015 Civic used two main gasoline engines: the 1.8-liter and the 2.4-liter for sportier variants. In both cases the sensor is mounted to the engine block, but the precise access point differs slightly. Use this as a quick guide to locating it.
- 1.8L inline-4 (R18A1) engine: Knock sensor is mounted to the side of the cylinder block toward the firewall, just above the transmission bell housing, and faces the engine bay. It’s typically under or beside the intake manifold and can be accessed from the top with the air intake removed.
- 2.4L inline-4 (Si variant): Knock sensor sits on the side of the cylinder head/upper block area, commonly toward the passenger side rear of the engine. Access may require removing portions of the air intake or shielding in the engine bay.
Note: Some model configurations and production dates may place the sensor slightly differently. If you’re replacing or diagnosing the KS, consult the service manual for your VIN to confirm the exact mounting location and connector type.
Quick access steps to locate the KS
For a fast, practical approach, follow these steps to find the knock sensor without guessing in a dim engine bay.
- Disconnect the negative battery cable and remove any obstructing intake components to improve visibility.
- Trace the engine wiring harness from the engine control unit toward the center of the engine bay; the KS connector will be a small 2- or 3-pin plug.
- Inspect the engine block surface for a small, round sensor threaded into the block with a short harness leading to the connector.
- Note the sensor’s orientation and the surrounding metal casting to distinguish it from nearby plugs and sensors.
Once located, you can test or replace the KS following Honda's service procedures, ensuring the connector is clean and the sensor threads are free of debris before reassembly.
Summary
In the 2015 Honda Civic, the knock sensor is mounted on the engine block, typically on the side near the cylinder head and toward the firewall. Access varies by engine variant, with the 1.8L engine placing the sensor on the block side behind the intake and the 2.4L variant placing it near the head area; always confirm with the vehicle’s service manual for your VIN. Accurate locating aids diagnosis and safe replacement.