Parts for your 2017 Subaru Impreza-Camshaft sensor

2017 Subaru Impreza Camshaft Sensor — What It Does and When to Replace It

On the 2017 Subaru Impreza (GK/GT) with the 2.0-litre FB20D engine, a camshaft sensor is absolutely fitted and used. Subaru’s factory service information for 2017MY Impreza (Engine Diagnostics—FB section) lists diagnostic trouble codes such as P0340/P0341/P0345 for the Camshaft Position Sensor circuits, and the Subaru parts catalogue shows two camshaft position sensors (one per cylinder head) for this model. The engine’s dual AVCS (variable valve timing) strategy in the same manual also references camshaft position inputs for phasing control.

In this Impreza, the camshaft sensor’s job is to tell the engine control unit exactly where each cam is in relation to the crank. That lets the ECU fire the injectors and spark at the right moment and finely trim the AVCS on both banks for smooth idle, torque, fuel economy, and emissions. If a sensor goes out of whack, the car may crank longer, idle roughly, feel flat on acceleration, or drop into a limp strategy with the check engine light on.

There’s no scheduled replacement interval for the camshaft sensors, they’re solid-state and usually last the life of the vehicle. As part of regular servicing, it’s smart to give the connectors a quick once-over: check for oil wicking into the plug, brittle wiring, or loose retainers. Because these sensors live on the ends of the cylinder heads, heat and the odd oil mist can age the plug seals over time.

If replacement is needed, it’s a straightforward, driveway-friendly job for many owners:

• Disconnect the battery and remove the engine cover or intake ducting for access.
• Unplug the sensor, remove the retaining bolt, and withdraw the sensor straight out.
• Lightly oil the new O-ring, seat the new sensor, and tighten the bolt to the factory spec from the Subaru service manual.
• Reconnect, clear any codes, warm the engine, and take a short drive so the ECU can relearn cam/crank correlation.

When diagnosing, avoid throwing parts: confirm power, ground, and clean signal at the sensor, and inspect the harness where it passes close to the timing cover. Oil control valves and dirty AVCS oil screens can mimic cam sensor faults, so fresh, correct-spec oil and a quick check of those filters during service is time well spent. Stick with genuine or high-quality aftermarket sensors—cheapies can cause intermittent faults that are harder to chase than the original issue.

Typical symptoms of a crook camshaft sensor on a 2017 Impreza:

1. Check engine light with cam sensor DTCs (e.g., P0340/P0345).
2. Hard starting, stumbling idle, or stalling.
3. Sluggish performance and higher fuel use, especially when warm.

FAQs

How many camshaft sensors does a 2017 Subaru Impreza have?
This model has two—one on each cylinder head. They work with the crankshaft sensor and the AVCS oil control system to manage valve timing, fuelling, and spark.

Is it safe to drive with a failing camshaft sensor?
It might run, but it can stall, lack power, and use more fuel. Prolonged driving can stress the catalytic converter. It’s best to diagnose and fix it promptly.

Does a new camshaft sensor need programming?
No special programming. After installation, clear fault codes, warm the engine, and drive normally so the ECU can relearn cam/crank sync.