Parts for your 2015 Subaru Forester-Crank angle sensor

2015 Subaru Forester crank-angle sensor — what it does and how to look after it

Based on Subaru’s factory service information for the 2015 Forester (covering FB25 2.5L and FA20 2.0L engines), the OEM parts catalogue, and the Subaru OBD-II diagnostic charts for DTCs P0335–P0336, this model absolutely uses a crank-angle sensor. Subaru typically calls it the crankshaft position sensor (CKP), but in practice “crank-angle sensor” and “CKP” refer to the same part.

This sensor sits at the rear of the engine by the bellhousing and reads a toothed wheel on the crank. It feeds exact engine speed and crank angle back to the ECU so it can fire the coils, meter fuel, and sync with the cam sensors for variable valve timing. Without a valid signal, the Forester can crank but won’t start, with a weak or intermittent signal it may start but run poorly, surge, or stall when hot.

As a service item, it’s not something that needs doing every set number of kilometres. What makes sense is a quick health check any time the Forester’s in for a service: look for damaged wiring looms near the sensor, oil contamination around the O-ring area, loose brackets that might let the harness rub, and metal debris stuck to the sensor tip. Keeping connectors clean and properly latched does more for reliability than any fancy trick. Avoid solvents or aggressive scraping on the sensor face, a soft cloth is fine.

If replacement is needed, it’s a straightforward one-bolt job for a competent DIYer or tech:

• Disconnect the battery negative and let the vehicle sit a few minutes.
• Access the sensor at the rear of the engine under the bonnet, remove intake ducting if it’s in the way.
• Unplug the connector, remove the retaining bolt, and ease the sensor out, the O-ring can stick.
• Lightly oil the new O-ring, seat the new sensor squarely, and snug the bolt. Route the loom like factory.
• Clear any fault codes and road-test to confirm clean starts and stable idle.

Use a genuine Subaru or high-quality equivalent sensor, cheap units can cause sync errors or recurring MIL lights. If a crank-angle fault persists after fitting a good sensor, check the cam sensors, wiring integrity, and mechanical timing before throwing more parts at it.

Popular questions about 2015 Subaru Forester crank-angle sensors

Where is the crank-angle sensor on a 2015 Forester?
On FB25 and FA20 engines it’s mounted at the rear of the engine adjacent to the bellhousing. It reads a reluctor on the crankshaft. Access is usually from the top under the bonnet, though some prefer reaching from underneath depending on tools and intake layout.

Can it be driven with a failing crank-angle sensor?
It might run briefly, then stall without warning, or refuse to restart once hot. That’s risky in traffic and can leave the driver stranded. Best approach is to scan for codes (P0335/P0336 are common), avoid unnecessary driving, and sort the fault promptly.

Does a new sensor need programming?
No special programming is normally required on this model. Clear any stored codes, start the engine, and the ECU will use the new signal straight away. If codes return, look for wiring faults, poor connections, or timing issues rather than trying to “relearn” the sensor.