Parts for your 2009 Subaru Legacy-Crank angle sensor

2009 Subaru Legacy crank-angle sensor: what it does and when to replace it

Technical sources confirm the 2009 Subaru Legacy does use a crank-angle sensor (commonly called the crankshaft position sensor or CKP). The Subaru Factory Service Manual for 2009 Legacy/Outback (BP/BL), engine diagnostics section for DTC P0335–P0339, describes the CKP’s role in timing control. Subaru’s parts catalogue also lists a genuine “Sensor – Crankshaft Position” for EJ-series engines fitted to this model year, and independent references such as Autodata and the Haynes Subaru Legacy & Outback manual document testing and replacement procedures. So yes, it’s fitted and it matters.

On a 2009 Legacy, the crank-angle sensor feeds the ECU precise crank speed and position data so the engine can fire the coils and injectors at exactly the right moment. It works alongside the cam sensors to enable sequential fuel injection, stable idle, clean cold starts and decent fuel economy. If the signal drops out, the ECU can’t reliably time spark or fuel, which is why a failed CKP often means a no-start, sudden stalling, or hard starting when hot. Typical dash clues are a check engine light with codes like P0335 and a dead or jumpy tacho while cranking.

Replacement is straightforward for a competent DIYer. It’s mounted on the front of the engine and reads a toothed wheel on the crank. Usual steps are to disconnect the battery, unplug the connector, remove the retaining bolt, ease out the sensor, then fit a new OEM-quality unit with a lightly oiled O-ring. Route the loom correctly and tighten the bolt to factory spec. Clearing fault codes and performing a brief idle relearn helps the ECU settle quickly. If in doubt, a scan tool that can read live data (crank rpm while cranking) is gold for diagnosis.

There’s no set service interval for the CKP, but as part of regular servicing it’s smart to:

• Inspect the connector and wiring for oil contamination or brittle insulation.
• Check for engine oil leaks that could wick into the plug.
• Verify clean mounting and correct sensor gap (fixed by design on OE sensors).

Owners should stick with genuine or reputable aftermarket sensors, cheap copies can cause intermittent no-starts or random stalls. Given how critical timing is on the EJ engine, a healthy crank-angle sensor keeps the Legacy starting first pop and running sweet across Kiwi and Aussie conditions.

Popular questions

Does a 2009 Subaru Legacy have a crank-angle sensor, and where is it?

Yes. It’s fitted from factory. It’s mounted on the front of the engine, reading a trigger wheel on the crank. Access is from the top with basic hand tools, and it’s unplug-bolt-swap simple for most home mechanics.

What are the signs the crank-angle sensor is failing?

Common signs include hard starting (especially hot), random stalling, a no-start with no tacho movement, poor acceleration, and the check engine light with codes like P0335. Intermittent faults may show up as brief cut-outs over bumps or when hot.

Is it safe to drive with a dodgy crank-angle sensor?

Not really. It can stall without warning and may leave the driver stranded. If symptoms are present, diagnose promptly and replace the sensor to avoid unsafe driving and potential catalyst damage from misfires.