Parts for your 2018 Subaru Impreza-Crank angle sensor

2018 Subaru Impreza crank-angle sensor: what it does, why it matters, and how to look after it

Yes, the 2018 Subaru Impreza is fitted with a crank-angle sensor (more commonly called a crankshaft position sensor or CKP). Subaru’s 2017/2018MY Impreza Service Manual for the FB-series 2.0L engine outlines the CKP’s role in determining crank angle and engine speed for ignition and fuel control, and documents related diagnostics such as DTC P0335–P0339 for the crank sensor circuit. The official Subaru parts catalogue also lists a crankshaft position sensor for 2018 Impreza models (e.g., Subaru PN 22053AA054, superseding earlier numbers). These technical sources confirm the sensor is integral to engine management on this vehicle.

On the 2018 Impreza, the crank-angle sensor is the engine’s timekeeper. It tracks the exact position and rotational speed of the crankshaft so the ECU can fire the coils and inject fuel at precisely the right moment. Working in tandem with the cam sensors, it keeps everything in sync from cold start to highway cruise. Lose that signal and the ECU can’t reliably time spark or injectors, which is why a failed sensor can cause long cranks, stalling or a no-start.

Day to day, there’s nothing owners need to “service” inside the sensor. It’s a solid-state Hall or magnetic pickup with no scheduled replacement interval. What’s smart, though, is a quick look during regular servicing: check the harness for chafing, make sure the connector is clean and latched, and keep oil leaks or coolant dribbles away from the plug. On the FB20D engine, the sensor is mounted on the back of the block near the bellhousing area, it’s held with a single bolt and sealed with an O-ring, so a light wipe to remove grime is fine—strong solvents aren’t.

If the dash lights up with a check engine lamp and the car throws a P0335-type code, or there are telltales like intermittent stalling, rough idle, or a crank-no-start when hot, it’s time for diagnosis. A proper scan tool and a simple wiring check will usually pinpoint the fault. Replacement is straightforward for a competent tech—disconnect the battery, unplug the connector, remove the retaining bolt, swap the sensor and O-ring, then refit and torque to the service manual spec. Plan around half an hour to an hour. Once installed, clear codes and perform any idle/ECU relearn as required. Stick with a genuine Subaru sensor or a premium aftermarket equivalent so the signal quality stays crisp and reliable over our hot summers and cool, damp winters across Australia and New Zealand.

Typical warning signs owners notice include:

• Hard starting or a no-start when hot, then it fires up after cooling down
• Sudden stall at idle or when rolling to a stop
• Check engine light with crank sensor-related fault codes

Left ignored, a flaky crank-angle sensor can leave the Impreza stranded. Sorting it early keeps the commute easy and the kilometres carefree.

FAQs

Where is the crank-angle sensor on a 2018 Subaru Impreza?
On the FB20D engine it’s mounted at the rear of the engine block near the bellhousing. Access is typically from above with the intake hardware in place, or from underneath on a hoist. The Subaru service manual shows the exact location and connector layout for quick identification.

What are the common symptoms of a failing crank-angle sensor?
Owners often report long cranks, random stalling, rough idle and a check engine light. Fault codes like P0335–P0339 are common. Sometimes it’s heat-related—fine when cold, then it drops out once everything’s hot under the bonnet.

Does the crank-angle sensor need routine replacement?
It’s not a scheduled replacement item. Replace it only if it’s faulty, damaged, oil-soaked, or if diagnostics confirm a bad signal. During regular servicing, a quick visual of the wiring and connector is all that’s required.