Parts for your 2010 Subaru Legacy-Camshaft sensor

2010 Subaru Legacy camshaft sensor — what it does and how to look after it

Yes, the 2010 Subaru Legacy uses camshaft position sensor(s). This is supported by Subaru’s 2010MY Legacy/Outback Factory Service Manual (engine diagnostics and wiring diagrams show CMP inputs and DTCs such as P0340/P0341 and P0345/P0346), and by Subaru parts catalogues listing camshaft position sensors across the 2.5i (EJ253), 2.5GT (EJ255) and 3.6R (EZ36) variants. These engines run sequential fuel injection and variable valve timing, which require a cam signal to confirm cam phasing relative to the crank.

On this model, the camshaft sensor tells the ECU exactly where the cam(s) are in their rotation. The ECU pairs that with the crank signal to sync injection and ignition, stabilise cold starts, and control AVCS where fitted. If the signal goes missing or messy, the car can be hard to start, drop power, or throw a Check Engine Light. It may also default to a limp strategy to protect the engine.

Typical signs the cam sensor is unhappy include a long crank before it fires, rough idle, random stalling at lights, a flat spot under load, and worse fuel economy. The ECU commonly logs P0340/P0341 (Bank 1) and, on dual-bank setups, P0345/P0346 (Bank 2). A proper diagnosis uses a scan tool to check live data and, ideally, a scope to see the cam/crank waveform relationship.

• Servicing tips: the sensor itself isn’t a regular replacement item, but it pays to keep the connector clean and the engine oil fresh. These sensors live in the head and don’t love sludgy oil or heat-soaked, brittle wiring.
• Replacement pointers: on the EJ253 there’s typically one sensor on the right-hand head, EJ255 and EZ36 engines use two (one per bank). Disconnect the battery, unplug the connector, remove the small retaining bolt, twist and pull the sensor out, swap the O-ring, lightly oil it, refit, and torque to the spec in the Subaru manual. Clear codes and verify sync/idle quality.
• Parts choice: genuine or high-quality OEM-equivalent sensors are best. Cheapies can cause intermittent faults that are a pain to chase.

If the car has done big kilometres, has oil leaks at the head, or shows intermittent cam/crank correlation codes, a fresh sensor and O-ring can be good preventative maintenance. Anyone chasing persistent cam sensor faults should also check harness routing and shielding near the timing cover and exhaust — Aussie and Kiwi summers can cook looms over time.

Popular questions

How many camshaft sensors does a 2010 Subaru Legacy have?
It depends on the engine. The 2.5i (EJ253) generally runs a single camshaft sensor, while the turbo 2.5GT (EJ255) and 3.6R (EZ36) use one sensor per bank. The Subaru service manual wiring diagrams show the exact count and locations for each variant.

Can they drive with a failing cam sensor?
It might run, but starting can be hit-and-miss and performance will suffer. The ECU may fall back to a safe strategy. Continuing to drive can stress the catalytic converters with misfires, so it’s better to diagnose and fix promptly.

Do cam sensors need routine replacement?
They’re not a scheduled service item. That said, age, heat and oil contamination can cause slow failures. If there are related DTCs, hard starts, or intermittent stalling after warm-up, testing and replacing the sensor and O-ring is sensible.