Parts for your 2015 Subaru Forester-Map sensor

2015 Subaru Forester MAP sensor — what it does, why it matters, and how to look after it

Yes, the 2015 Subaru Forester uses a MAP (Manifold Absolute Pressure) sensor. Technical sources back this up: the Subaru Factory Service Manual for MY2015 Forester (Fuel Injection/Engine Diagnostics sections) identifies a “Manifold Absolute Pressure Sensor,” OBD-II diagnostics include MAP-related DTCs such as P0106/P0107/P0108, and the Subaru parts catalogue lists a MAP sensor for both FB25 (2.5i) and FA20F (XT turbo) engines. Subaru’s technical information also notes the Forester runs both a MAF and a MAP, the MAF measures incoming air at the intake, while the MAP tracks pressure in the manifold for load calculation, barometric correction, and boost control on the turbo models.

The MAP sensor’s job is to read the absolute pressure in the intake manifold and feed that to the ECU. From there, the ECU calculates engine load to fine-tune fuel, ignition timing, and (on the XT) boost and wastegate behaviour. A healthy sensor keeps cold starts tidy, throttle response crisp, and fuel economy on-song.

While Subaru doesn’t schedule MAP sensor replacement at fixed kilometre intervals, it’s smart to include simple checks during regular servicing:

• Scan for MAP-related codes (P0106–P0108) and compare live data to expected kPa at key-on (near ambient barometric pressure) and at idle (significantly lower on NA engines).
• Visually inspect the sensor body, connector, and harness for corrosion, oil intrusion, or broken locks.
• Check the O-ring seal, replace if flattened, cracked, or oil-soaked.
• If contamination is suspected, carefully clean the port using electronics-safe cleaner and a gentle touch. Don’t poke the diaphragm or blast with compressed air.

Symptoms of a dodgy MAP include hard starts, rough idle, lazy throttle, higher fuel use, sootier exhaust, and a check engine light. On FA20F turbo models, a faulty reading can also cause odd boost behaviour or limp mode.

Replacement is straightforward: disconnect the battery, unplug the connector, remove the fixing screws, lift out, swap the O-ring, and reinstall. Tighten only to factory spec (snug, not gorilla-tight), reconnect, then start and let the ECU relearn idle for a few minutes. Always use a quality OE-equivalent sensor, cheapies can skew readings and cause more grief than they fix.

For Kiwi and Aussie owners doing a lot of dusty or stop–start driving, adding a quick MAP check to every 20,000–30,000 km service pays off. It keeps the Forester running sweet and avoids chasing your tail on avoidable drivability faults.

Popular question: Does the 2015 Forester have both a MAF and a MAP sensor?

It does. The MAF measures incoming air at the intake, while the MAP reads manifold pressure. Subaru’s service literature shows the ECU uses both signals for accurate load calculation, altitude correction, and, on the XT, boost control. Losing either tends to trigger fault codes and rough running.

Popular question: How often should the MAP sensor be replaced?

There’s no fixed replacement interval. Treat it as condition-based: inspect at regular services, clean gently if contaminated, and replace only if readings are out of spec or codes like P0106–P0108 persist after checks. Many original sensors last well past 150,000 km when the intake tract is kept clean.

Popular question: What are the signs a MAP sensor is failing on a 2015 Forester?

Common giveaways include hard starting, hunting or rough idle, flat spots on acceleration, poor fuel economy, and the check engine light with MAP-related codes. Turbo XTs may also show unstable boost or limp mode. Confirm with live-data testing before swapping parts.