Parts for your 2015 Subaru Legacy-Map sensor

2015 Subaru Legacy MAP sensor – purpose, care, and when to replace

For the 2015 Subaru Legacy (FB25 2.5L and EZ36 3.6L), a MAP sensor is fitted from factory. This is documented in the Subaru Factory Service Manual for 2015MY Legacy/Outback (Fuel Injection/Engine Control sections), Subaru Technical Information System (STIS), and the Genuine Subaru Parts Catalogue, all of which list a Manifold Absolute Pressure sensor mounted on the intake manifold. Diagnostic routines for DTCs P0106–P0108 in those manuals also confirm MAP sensor use on these engines.

The MAP sensor’s job is to measure absolute pressure inside the intake manifold. The ECU uses that pressure signal to calculate engine load, fine‑tune fuelling and ignition timing, and cross‑check the MAF signal. On the naturally aspirated Legacy, it’s key for smooth throttle response, stable idle, cold starts, and keeping fuel economy in check. Because it reports real‑time manifold pressure, it helps the ECU adjust quickly when the driver jumps on the throttle or when air density changes with altitude or weather.

There’s no scheduled replacement interval for the MAP sensor, and Subaru’s manuals don’t call for routine cleaning. Under the bonnet, it’s a simple direct‑mount unit on the intake manifold with an O‑ring and a single electrical connector. During regular servicing, it’s worth doing a quick visual: make sure the connector is snug, the harness isn’t rubbed through, and the O‑ring area is dry and tight. If oil mist or dust has built up around the port, a light spray of electronics‑safe cleaner can help, but don’t poke anything into the sensor.

Typical clues the MAP sensor or its circuit needs love include:

• Rough idle, hard starting, flat spots on take‑off
• Heavier fuel use and a petrol smell
• Check Engine Light with codes like P0106, P0107 or P0108

Replacement is a quick driveway job for most: disconnect the battery (nice to have, not mandatory), unplug the connector, remove the retaining screw, swap in the new unit with a fresh O‑ring, and refit. Torque the fastener to the value in the Subaru service manual to avoid cracking the housing. After starting, let the ECU idle for a few minutes to settle trims, clear any stored codes with a scan tool. Using a quality OEM‑equivalent sensor pays off in stable idle and crisp throttle behaviour, and helps the Legacy keep its fuel use tidy across Aussie and Kiwi kilometres.

Popular questions

Does the 2015 Subaru Legacy have a MAP sensor or only a MAF?
Yes, it has both. Subaru’s 2015 service information shows a Manifold Absolute Pressure sensor on the intake manifold, working alongside the MAF so the ECU can calculate load accurately and keep drivability smooth.

Where is the MAP sensor on a 2015 Legacy?
It’s bolted to the intake manifold near the throttle body under the bonnet. Look for a small, rectangular sensor with a single plug and an O‑ringed snout into the manifold.

Do you need to program anything after replacing the MAP sensor?
No special coding is required. Clear any fault codes, start the engine, and allow a short idle so the ECU can relearn trims. A brief drive cycle helps finalise adaptations.