Parts for your 2005 Subaru Impreza-Camshaft sensor

2005 Subaru Impreza Camshaft Sensor: Purpose, Service Tips, and When to Replace

Yes, the 2005 Subaru Impreza is fitted with a camshaft position sensor (CMP). Technical references including the Subaru Factory Service Manual for MY2005 Impreza, Subaru’s Technical Information System (wiring diagrams), and common workshop databases (e.g., Mitchell1/Alldata) all show a camshaft position sensor circuit, related fault codes (P0340/P0341), and replacement procedures. Naturally aspirated models typically use one CMP, while AVCS-equipped turbo models (such as many AU/NZ WRX variants) use two—one per cylinder bank.

The camshaft sensor tells the engine control unit exactly where the camshaft is in its rotation. That lets the ECU sync fuel injection and ignition with the crankshaft position for smooth starts, clean idle, and proper power under load. On AVCS-equipped engines, the sensor also lets the ECU monitor and control cam timing advance, which helps torque and fuel economy. If the sensor plays up, drivers may notice hard starting, rough running, misfires, sluggish performance, higher fuel use, or a check engine light with CMP-related fault codes.

This sensor isn’t a regular service item like oil or filters, but it’s smart to keep an eye on it during routine servicing. Under the bonnet, check the sensor connector and wiring loom for brittle insulation, green corrosion, or oil contamination from cam cover leaks. Oil wicking into the plug can skew the signal. On higher-kilometre cars, a quick visual once or twice a year is cheap insurance.

Replacement is straightforward for most home mechanics and workshops: disconnect the battery, unplug the sensor, remove the small retaining bolt, and withdraw the sensor. A light smear of clean engine oil on the new O-ring helps it slide in. Refit and torque the fastener to the spec listed in the Subaru service manual, then clear codes and road-test. If faults persist, inspect the crank sensor, timing belt alignment (on belt-driven engines), and ECU grounds, as these can mimic CMP faults.

Quality matters here—go OEM or a reputable aftermarket brand to avoid intermittent issues. If the vehicle has two sensors (AVCS models), diagnose methodically before replacing parts. With a healthy camshaft sensor, the 2005 Impreza starts crisply, idles smoothly, and delivers the dependable, no-drama drive Aussies and Kiwis expect.

• Common symptoms: hard starting, rough idle, misfires, poor fuel economy, and check engine light (P0340/P0341).
• Basic care: inspect wiring/plug, fix oil leaks near the sensor, and verify timing belt health.
• Best practice: use quality parts and confirm torque specs from the Subaru FSM.

FAQs

Where is the camshaft sensor on a 2005 Subaru Impreza?
It’s mounted on the cylinder head and reads a trigger on the camshaft. Most naturally aspirated 2.0/2.5 models use a single sensor, while many AVCS-equipped turbo models use one on each bank. Access is typically from the top under the bonnet near the timing end or rear of the head, depending on engine variant.

What are the signs a camshaft sensor is failing on a 2005 Impreza?
Expect hard starting, uneven idle, hesitation, misfires, higher fuel use, and a check engine light. Scan tools often show P0340 or P0341. Before swapping parts, confirm wiring integrity and check for oil contamination at the connector.

Do all 2005 Impreza models have two camshaft sensors?
No. Many naturally aspirated models have one sensor. AVCS-equipped turbo models commonly have two—one for each cylinder bank—to support variable valve timing. Check the VIN, engine code, or the Subaru service manual for your exact setup.