Parts for your 2020 Subaru Legacy-Crank angle sensor

2020 Subaru Legacy crank-angle sensor — what it does and how to look after it

Yes, the 2020 Subaru Legacy is fitted with a crank-angle sensor (more commonly called the crankshaft position sensor). Subaru’s factory service information for the 2020 Legacy/Outback platform (FB25 2.5‑litre and FA24 2.4‑litre turbo engines) details diagnostics for DTCs P0335–P0339 and test procedures for the crankshaft position sensor, and Subaru’s parts catalogues list a dedicated crank sensor for these models. Those technical sources confirm the sensor is present and critical to engine management.

On this model, the crank-angle sensor reads a toothed reluctor on the crankshaft and sends a precise speed and position signal to the engine control module (ECM). The ECM uses that signal to fire the spark at the right moment, time the fuel injection, and sync with the camshaft sensors for proper valve timing control and misfire monitoring. Without a clean, accurate crank signal, the engine may crank but not start, stumble, or cut out intermittently.

• Common symptoms when the sensor or its wiring plays up: hard starting or no start, random stalling (especially hot), rough idle, reduced power, erratic tacho, and stored fault codes like P0335/P0336.
• It isn’t a scheduled service item, but it benefits from periodic checks of the connector, harness routing, and nearby oil leaks under the bonnet.

Replacement is straightforward for a competent technician and typically doesn’t require coding. Good practice for a 2020 Legacy includes:

1. Disconnect the negative battery terminal and allow the engine to cool.
2. Access the sensor on the engine block where it reads the crank reluctor, unplug the connector, remove the retaining fastener, and withdraw the sensor carefully.
3. Lightly oil the O‑ring on the new OEM‑quality sensor, install, and tighten the fastener to the factory spec. Avoid overtightening.
4. Reconnect the harness, ensure the loom is clipped away from heat and moving parts, reconnect the battery, clear any DTCs, and road test. Perform an idle relearn if needed after battery disconnect.

Because the crank signal is foundational, cheap pattern parts can cause intermittent faults—stick with genuine or OE‑equivalent. If drivability issues persist after replacement, inspect the cam sensors and wiring, as the ECM relies on both to stay in sync.

Technical sources referenced: Subaru Factory Service Manual for 2020 Legacy/Outback (Engine Diagnostics: DTC P0335–P0339), Subaru Technical Information System procedures, and Subaru parts catalog listings for the crankshaft position sensor applicable to FB25 and FA24 engines.

Popular questions about the 2020 Subaru Legacy crank-angle sensor

Does the 2020 Legacy actually have a crank-angle sensor?
It does. Subaru documentation lists a crankshaft position (crank-angle) sensor for all 2020 Legacy engines. It works with the cam sensors to control ignition timing, fuel delivery, and misfire detection.

After replacing the sensor, is programming or a relearn required?
Generally, no coding is required on this model. Clear any fault codes, verify live data, and perform an idle relearn if the battery has been disconnected. A short drive cycle helps the ECM complete readiness checks.

What usually causes these sensors to fail?
Heat soak, vibration, oil contamination at the connector, and damaged wiring are the usual culprits. Ensuring the harness is clipped properly and fixing any oil leaks nearby will help the new sensor live a long life.