Parts for your 2015 Subaru Legacy-Camshaft sensor

2015 Subaru Legacy camshaft sensor — what it does and when to replace it

Yes, the 2015 Subaru Legacy uses camshaft position sensors. Subaru’s factory service manual for the 2015 Legacy/Outback (BN/BS platform) lists the camshaft position sensor in the Engine Diagnostics section, and the Subaru Genuine Parts catalogue shows “Sensor – Camshaft Position” for this model. On the 2.5i (FB25) there are typically two sensors (one per cylinder head), and on the 3.6R (EZ36) there are four (one per cam). These sensors are essential for sequential fuel injection, ignition timing, and Subaru’s AVCS variable valve timing strategy.

On this model, the camshaft sensor reads a toothed target on the cam to tell the ECU exactly where each cylinder is in its cycle. That lets the ECU fire injectors and spark at the right moment, and advance or retard the cams for better power, economy, and smoothness. If a sensor goes out of whack, the dash will usually light up with a Check Engine warning and store fault codes like P0340/P0341, and the car may crank longer, idle rough, feel flat, or drop into a limp mode.

There’s no scheduled maintenance for the camshaft sensors themselves, but good oil and filter changes help AVCS behave properly and keep the timing events clean. Under the bonnet, it’s worth a quick look during servicing to make sure the sensor connectors are clipped in, wiring isn’t rubbed through, and there’s no oil wicking into the plug. Any oil contamination at the sensor’s O-ring should be sorted with a new seal.

If replacement is needed, it’s a straightforward job for a competent DIYer or mechanic:

• Confirm the fault with scan data and live cam/crank correlation.
• Disconnect the battery negative, unplug the sensor, remove the single hold-down bolt, and twist the sensor out gently to protect the O-ring.
• Lightly oil the new O-ring, seat the new sensor squarely, and torque the bolt to the factory spec from the service manual.
• Clear codes, start the engine, and verify stable cam angle and no pending faults. An idle relearn may be required.

Use a quality OEM-equivalent sensor, mixing brands side-to-side on the FB25 can cause unnecessary correlation hiccups. If the Legacy still throws correlation codes after a new sensor, it’s time to inspect the timing, AVCS oil control valves, and wiring continuity per the Subaru service literature.

Popular questions

Where are the camshaft sensors on a 2015 Subaru Legacy?
On the 2.5i FB25, each sensor sits near the front of each cylinder head, behind the timing cover area, reading the cam sprocket. The 3.6R EZ36 has one on each cam, so you’ll find a sensor at each head for both intake and exhaust cams. Access is typically from the top with basic hand tools.

Can a bad camshaft sensor damage the engine?
It’s unlikely to cause mechanical damage by itself. However, it can trigger poor running, hard starts, and increased fuel use. Prolonged driving while the ECU is guessing timing isn’t ideal, so it’s best to diagnose and replace the sensor sooner rather than later.

Do I need to replace both sensors on the FB25 at the same time?
Not strictly, but many techs prefer to replace sensors in pairs on the FB25 to keep signal quality consistent side-to-side. If one failed due to age or contamination, the other may not be far behind.