Parts for your 2017 Subaru Legacy-Crank angle sensor

2017 Subaru Legacy (Liberty) crank-angle-sensor — purpose, servicing and replacement

Referencing technical sources: The Subaru factory Service Manual for the 2015–2019 Legacy/Liberty (Engine Diagnostics section listing DTC P0335/P0336) and the Subaru OEM parts catalogue both specify a crankshaft position sensor (often called a crank-angle sensor) for the 2017 Subaru Legacy/Liberty with FB25 and EZ36 engines. That means this model is definitely fitted with, and relies on, a crank-angle sensor.

The 2017 Subaru Legacy’s crank-angle sensor is the ECU’s timekeeper. It tracks the exact rotational position and speed of the crankshaft so the engine computer can fire the injectors and spark at just the right moment. Paired with the cam sensors, it keeps timing spot-on for smooth idling, strong pull, and clean emissions. If that signal goes missing or gets noisy, the ECU can’t confidently control the show, which is why a faulty sensor often leads to hard starts or a sudden stall.

Typical warning signs include an intermittent no-start after a warm soak, uneven idle, misfire-like hesitation, random stalling when coming to a stop, or the tacho dropping to zero while cranking. The check engine light may flag codes like P0335 or P0336. Because the unit sits near heat, oil vapour, and vibration, wiring and connector integrity matter just as much as the sensor itself.

There’s no set replacement interval in regular servicing for the crank-angle sensor, it’s a replace-when-faulty item. During scheduled services, it’s smart to eyeball the harness routing under the bonnet, ensure the connector is clean and latched, and confirm there’s no oil contamination creeping into the plug. Keeping the battery and grounds in good nick helps the ECU read the sensor cleanly, too.

When replacement is needed, use a quality OEM-equivalent sensor. Disconnect the battery, unplug the sensor at the front of the engine near the timing cover, remove the retaining bolt, and ease the sensor straight out. Lightly oil the O-ring on the new unit, seat it without forcing, and tighten the bolt to the factory spec from the service manual. After installation, clear any stored codes and perform an idle relearn if required. If issues persist, inspect the trigger wheel and wiring rather than throwing more parts at it. A brief road test confirming stable idle and crisp starts wraps the job nicely.

Where is the crank-angle sensor on a 2017 Subaru Legacy?

It’s mounted at the front of the engine near the timing chain cover, reading the crankshaft’s trigger pattern. Access is from above under the bonnet, the connector and single retaining bolt are straightforward to reach on most trims.

Can a bad crank-angle sensor cause a no-start?

Absolutely. If the ECU can’t see accurate crank speed and position, it won’t deliver spark or fuel at the right time, so the engine may crank but not fire. It can also cause sudden stalling or rough running and will often log codes like P0335/P0336.

Does a new crank-angle sensor need programming?

No special programming is usually required. Fit the sensor, clear codes, and the ECU will use the signal straight away. Some workshops will perform an idle relearn to tidy up idle quality, which is quick and easy with a scan tool.