Parts for your 2007 Subaru Legacy-Map sensor

2007 Subaru Legacy MAP sensor — purpose, servicing and replacement

Based on technical sources including the Subaru Factory Service Manual for the 2007 Legacy/Liberty (Engine Diagnostics: DTC P0106–P0108), Subaru global parts catalogues listing MAP sensor part numbers for EJ253 and EJ255 engines, and Denso application data for Subaru MAP sensors, the 2007 Subaru Legacy is fitted with a Manifold Absolute Pressure (MAP) sensor. Both naturally aspirated 2.5i and turbo variants use a MAP sensor, on turbo models it’s also critical for boost control.

This sensor reads the absolute pressure inside the intake manifold, letting the ECU figure out engine load so it can trim fuel, ignition timing and, on turbo models, boost. It also helps with barometric corrections for altitude and provides a cross-check against the MAF sensor. The upshot for owners is smoother drivability, better economy and proper emissions control when the MAP is healthy.

• Common signs of a dodgy MAP: hard starting, rough idle, flat spots under acceleration, poor fuel economy, higher emissions and codes like P0106, P0107 or P0108.
• Quick checks during a service: inspect the electrical connector and wiring, ensure the sensor’s O-ring or seal is intact, and look for oil mist or carbon in the sensor port that can skew readings.
• With a scan tool: KOEO (key on, engine off) MAP should read close to local barometric pressure, at warm idle it should drop significantly (lower kPa = higher vacuum).

Replacement is straightforward and worth doing if readings are out of whack or there’s a confirmed fault. Quality matters here—OE-grade (e.g., Denso) tends to be accurate and reliable, which keeps the ECU happy and fuel trims tidy over the long haul.

1. Disconnect the battery (helps protect electronics and can clear trims).
2. Unplug the connector, remove the retaining screws/bolts and lift the sensor off the manifold.
3. Swap the O-ring/seal if supplied, seat the new sensor squarely and nip fasteners to spec—don’t overdo it on the alloy manifold.
4. Reconnect, clear fault codes and take a short mixed drive so the ECU relearns. A few kilometres of normal driving usually settles trims.

On turbo 2007 Legacy models, also make sure any short hose or passage to the sensor isn’t blocked with oil vapour residue. There’s no set replacement interval for the MAP sensor, but including a quick visual and scan check during major services is smart. It’s a small effort that prevents bigger headaches under the bonnet later.

Where is the MAP sensor on a 2007 Subaru Legacy?

It’s mounted on or near the intake manifold, close to the throttle body. On many EJ engines it sits on the manifold with two small fasteners and a sealed port into the plenum. The electrical connector points upward or toward the driver’s side, depending on engine variant.

Can a MAP sensor be cleaned or should it just be replaced?

If the port is contaminated with oil mist or carbon, a gentle clean of the manifold port and the sensor’s external port area can help. Avoid soaking the sensor in harsh solvents. If the internal sensing element has failed or readings are unstable, replacement is the fix.

Will a faulty MAP sensor cause poor fuel economy and rough idle?

Yes. Because the ECU relies on MAP for load calculations and baro correction, a bad signal can push fuel trims off target, causing rough idle, hesitation and higher fuel use. Fixing wiring or vacuum issues first is wise, then replace the sensor if it still tests out of range.