Parts for your 2020 Subaru Impreza-Camshaft sensor

2020 Subaru Impreza camshaft sensor — what it does, and when to service or replace it

Short answer: yes, the 2020 Subaru Impreza is fitted with camshaft position sensors. Subaru’s factory service information for the 2020MY Impreza (STIS/Factory Service Manual – Engine Diagnostics: Camshaft Position Sensor and related DTCs P0340/P0341) details testing and replacement of the sensor(s). The official Subaru parts catalogue for the same model year also lists camshaft position sensor assemblies for the FB-series 2.0L engine. So it’s absolutely relevant on this model.

On the Impreza’s FB20 engine, the camshaft sensor lets the ECU know exactly where the cam(s) are in relation to the crank. That live cam phase info is crucial for quick starts, smooth idle, sequential fuel injection, correct spark timing, and for the AVCS (active valve timing) system to advance or retard the cams as load and revs change. In plain terms, it’s how the car keeps timing crisp and fuel use tidy, and why it doesn’t feel doughy off the line.

It’s not a scheduled replacement item, but it does need attention if there are symptoms. Common signs of a crook cam sensor include hard starting, a rough or hunting idle, misfires, flat spots, increased fuel use, or the check-engine light with codes like P0340/P0341 or cam/crank correlation faults (P0016–P0019). Because the Impreza’s a boxer with two cylinder banks, you’ll typically find a sensor on each bank, both need to be healthy for the ECU to keep cam timing spot-on.

Before swapping parts, a good service approach is to scan for codes, check live data for cam/crank sync, and inspect the wiring and connectors for oil ingress or chafing. Clean, correct oil is surprisingly important here too — regular changes help keep the AVCS and the trigger wheels clean so the sensors read cleanly. Avoid blasting the back of the heads with a pressure washer, moisture in the connectors can cause intermittent dramas.

If replacement is needed, use a quality OE-equivalent sensor and a fresh O-ring. Under the bonnet, disconnect the battery negative, unplug the sensor, remove the retaining fastener, and wiggle the sensor straight out. Lightly oil the new O-ring, seat the new sensor squarely, and tighten the fastener to the factory spec from the service manual. Clear codes, road test, and confirm the cam/crank correlation and AVCS performance are back on song.

• Technical references: Subaru Factory Service Manual (STIS) 2020MY Impreza – Engine Diagnostics (Camshaft Position Sensor), and Subaru 2020 Impreza parts catalogue listing “Camshaft Position Sensor (Sensor Assy–Camshaft Position)”.

How many camshaft sensors does a 2020 Subaru Impreza have?

Most 2020 Impreza models with the FB20 engine have two camshaft position sensors, one per cylinder bank. This lets the ECU monitor cam phase for each side of the flat-four. If in doubt, check by VIN or consult the parts listing for your specific trim and market.

Is it safe to drive with a faulty camshaft sensor?

It may still run, but it can be hard to start, drop power, or stall, and it’ll often log fault codes. Prolonged driving can hurt fuel economy and, in some cases, risk catalyst damage from misfires. Best to diagnose and repair promptly to avoid bigger bills.

Where is the camshaft sensor located on the 2020 Impreza?

They’re typically mounted near the back or top of each cylinder head. Look for a small, two- or three-pin sensor held in with a single bolt and sealed by an O-ring. Access is decent from the top with basic hand tools.