Parts for your 2015 Subaru Xv-Knock sensor

2015 Subaru XV knock sensor — fitted, important, and worth looking after

Technical sources confirm the 2015 Subaru XV (GP-series, FB20 2.0‑litre boxer) is fitted with a knock sensor. The Subaru factory service manual for the GP/FB20 lists “Knock Sensor” inspection and diagnostics, Subaru’s Technical Information System (STIS) includes DTCs P0325, P0327 and P0328 for this model, and the OEM parts catalogue shows a dedicated knock sensor for the FB20 block. So yes — the knock sensor is relevant and used on the 2015 Subaru XV.

On the 2015 Subaru XV, the knock sensor is a smart little piezoelectric microphone bolted to the engine block that listens for detonation (knock). When it hears that sharp vibration, it signals the ECU to trim ignition timing just enough to protect the engine while keeping decent power and economy. For Aussie and Kiwi drivers running everyday 91–95 RON fuel, it’s a quiet guardian that helps the 2.0‑litre FB20 stay smooth and efficient under load, up hills, and on hot days.

It’s not a regular service item, but it deserves attention if the check engine light pops up or the XV feels flat. Typical symptoms of trouble include:

• Check engine light with codes P0325, P0327 or P0328
• Pinging under load, sluggish performance, or higher fuel use
• Intermittent hesitation as the ECU pulls timing to stay safe

Replacement is straightforward for a competent DIYer or any workshop. The sensor sits on the top-rear of the FB20 block under the intake manifold, secured by a single bolt with a two‑pin connector. Access usually involves removing the intake ducting/airbox and working carefully under the manifold. Key tips:

• Only install on clean, bare metal, no sealant, paint, or tape under the sensor
• Tighten to the factory torque spec — over‑ or under‑torque changes sensitivity
• Route the harness exactly like factory to avoid heat and interference
• Use quality/OEM parts, clear codes and road‑test to confirm normal knock control

There’s no fixed replacement interval, but it’s wise to inspect the connector and wiring during major services (for example, around spark plug time). Running decent petrol, keeping the cooling system healthy, and fixing intake leaks all reduce knock events — the sensor then has less work to do. If the sensor is cracked, oil‑soaked, or sets repeat DTCs even after wiring checks, replacement is the go. Most shops will wrap it up in under an hour.

Popular questions about the 2015 Subaru XV knock sensor

Where is the knock sensor on a 2015 Subaru XV?

It’s mounted on the FB20 engine block, roughly on the centreline at the top‑rear under the intake manifold, held by a single bolt with a two‑pin connector. Access is typically from above after removing the intake ducting or airbox.

Which fault codes point to a bad knock sensor on this model?

P0325 (circuit malfunction), P0327 (low input), and P0328 (high input) are the usual suspects on the XV’s FB20. Before condemning the sensor, check the harness, connector fitment, mounting surface, and correct torque — all of which can cause false readings.

Does the knock sensor need routine replacement?

No set interval. It’s replaced when faulty or contaminated, or if diagnostics confirm it’s out of spec. During major services, a quick visual check of the wiring and connector under the bonnet is sensible preventive care.