Parts for your 2002 Subaru Legacy-Camshaft sensor

2002 Subaru Legacy camshaft sensor — what it is, why it matters, and how to look after it

According to Subaru factory documentation, the 2002 Subaru Legacy is fitted with a camshaft position sensor. The Subaru Legacy/Outback 2000–2004 Service Manual (Engine Diagnostics, Camshaft Position Sensor section) and the 2002 Legacy/Outback Wiring System Manual identify the camshaft position sensor (often listed as “CMP”) as part of the engine control system across EJ20/EJ25 four-cylinder and EZ30 H6 variants. The manuals also define related diagnostic trouble codes such as P0340/P0341 for CMP signal faults and show the sensor in the harness and ECM pinouts. Genuine Subaru parts catalogues for that era list a camshaft position sensor (e.g., 22056AA06x) applicable to 2002 Legacy models. These technical sources confirm the sensor is relevant and used, the ECM relies on the CMP signal for synchronising fuel injection and ignition timing, and for misfire monitoring.

On a 2002 Subaru Legacy, the camshaft sensor tells the engine computer exactly where the cam is in its rotation, so it can fire injectors and spark at the right moment. That keeps cold starts tidy, idle smooth, and fuel economy respectable on Aussie and Kiwi roads. When the sensor goes out of whack, the ECU can struggle to sync with the crank sensor, leading to hard starting, misfires, rough running and the odd stall at the lights. The dash might light up with a Check Engine Lamp and store codes like P0340 or P0341.

There’s no routine replacement interval for the camshaft sensor — it’s a “replace when faulty” item. As part of regular servicing, it’s smart to glance over the sensor connector and loom under the bonnet, especially near the timing cover and left-hand cylinder head on EJ four-cyl engines, where heat and oil vapour can make plugs brittle. Keep an eye out for oil leaks that can wick into connectors, and make sure any timing belt work hasn’t pinched the wiring.

If replacement is needed, it’s typically a quick driveway job with basic hand tools. A scan tool to confirm codes, a 10 mm socket, and a clean rag will do the trick. Typical steps are: disconnect the battery, unplug the sensor, remove its small retaining bolt, ease the sensor out, lightly oil the new O-ring, refit, and tighten the bolt snugly to factory spec (don’t overdo it). Clear codes and start the engine, the ECU doesn’t need special programming and will relearn on the fly. On H6 models there are two cam sensors (one per bank), so diagnose which one’s grumpy before ordering parts. Use a quality OEM-equivalent sensor — cheap no-name units can cause intermittent faults that’ll drive anyone spare over a few hundred kilometres.

• Common signs: hard starts, rough idle, misfires, poor fuel economy, stalling, and codes P0340/P0341.
• Good practice: check connectors, secure loom routing, and rule out timing belt or cam sprocket issues if symptoms persist.

FAQs

Where is the camshaft sensor on a 2002 Subaru Legacy?
On EJ-series four-cylinder models, it’s typically mounted at the left-hand cylinder head near the camshaft — easy to reach from the top. On EZ30 H6 variants, there’s a sensor on each bank near the front timing cover area. Always verify by matching the connector and bracket per the service manual diagrams.

What are the symptoms of a failing camshaft sensor on this model?
Expect hard starting, rough idle, random misfires, stalling at low speed, and the Check Engine Lamp. The ECU will often store P0340 or P0341. Because the crank and cam signals work together, a dodgy CMP can feel like general ignition trouble, so a quick scan and visual check save guesswork.

Can it be driven with a bad camshaft sensor?
Sometimes the ECU will default to a less precise fuel strategy and keep the car going, but it may stall or run rich and can be unsafe in traffic. It’s best to sort it promptly to avoid getting stranded and to keep fuel use and emissions in check.