Parts for your 2001 Subaru Legacy-Camshaft sensor

2001 Subaru Legacy camshaft sensor — what it does and how to look after it

Yes, the 2001 Subaru Legacy uses a camshaft position sensor. This is documented in the Subaru Factory Service Manual for MY2001 Legacy/Outback (Engine Control System and Diagnostics sections), which lists DTCs P0340/P0341 for the Camshaft Position Sensor circuit. Subaru’s Electronic Parts Catalogue for the EJ-series engines fitted in 2001 (e.g., EJ251/EJ201/EJ204) also shows a “Camshaft Position Sensor” assembly (common part numbers include 22056AA071 and supersessions). Independent repair manuals covering 2000–2004 Legacy models likewise include test and replacement procedures for the cam sensor. So, it’s a relevant and fitted component on this model.

On the 2001 Legacy, the camshaft sensor helps the ECU figure out exactly where the cam is in its rotation so it can time fuel injection and spark properly, particularly during start-up and at idle. Paired with the crank sensor, it keeps the flat-four running sweet, saving fuel and cutting emissions. It’s mounted on the left-hand cylinder head near the cam sprocket, and reads a trigger on the cam as it spins.

There’s no scheduled maintenance for this sensor, it’s a replace-on-failure item. Still, a quick look under the bonnet during servicing is smart: check the connector for corrosion, make sure the harness isn’t rubbing through, and look for oil weeping past the sensor’s O-ring. Common symptoms of a crook cam sensor include hard starting (especially hot), rough idle, poor economy, hesitation, intermittent stalling, and an engine light with codes like P0340 or P0341.

Replacement is a straightforward driveway job for most owners:

• Disconnect the battery and remove nearby bits (airbox ducting makes access easier).
• Unplug the sensor, remove the small retaining bolt (10 mm head), and ease the sensor out.
• Lightly oil a new O-ring, seat the new sensor, and nip the bolt up to a light fastener spec (about 7 N·m). Don’t overtighten.
• Clear codes and road test. If the code returns, inspect wiring back to the ECU before blaming the new part.

Genuine Subaru sensors tend to be very reliable and are well matched to the EJ engine’s signal expectations. Quality aftermarket units can work fine, but if chasing an intermittent fault, they’re better off verified with a scope trace. For high-kilometre cars in Aussie and Kiwi heat, keeping connectors clean and away from exhaust heat shields will help the sensor live a long, drama-free life.

Popular questions about the 2001 Subaru Legacy camshaft sensor

Where is the camshaft sensor on a 2001 Subaru Legacy?
It’s fitted on the left-hand (driver’s side in RHD markets) cylinder head near the camshaft sprocket area. Access is from the top with the air intake ducting out of the way. Look for a small sensor with a single retaining bolt and a three-pin connector.

What are the signs of a failing camshaft sensor on this model?
Typical signs are hard starting, rough idle, flat spots on acceleration, random stalling, and an engine light with P0340/P0341. Fuel economy can suffer too. Because these symptoms can also come from wiring issues, always check the loom and connector before replacing the sensor.

Is it safe to drive with a bad camshaft sensor?
Sometimes the car will still run using the crank sensor alone, but it may start poorly and stumble. It can also stall at the worst time. Best bet is to sort it promptly—driving long distances with a dodgy signal risks more headaches than it saves.