Parts for your 2019 Subaru Legacy-Map sensor

2019 Subaru Legacy MAP sensor: purpose and servicing

Yes, the 2019 Subaru Legacy (BN series, FB25 2.5L and EZ36 3.6L) is fitted with a manifold absolute pressure (MAP) sensor. This is confirmed by Subaru’s factory service manual for the 2018–2019 Legacy/Outback engine control system (Diagnostics section), Subaru’s technical training for the FB-series engine management strategy, and the Subaru global parts catalogue, which lists a “Sensor Assembly – Manifold Absolute Pressure” for the applicable VIN ranges. The MAP sensor is mounted to the intake manifold, typically near the throttle body under the plastic engine cover.

On this model, the engine control unit uses both a MAF and a MAP sensor. The MAF handles primary airflow metering, while the MAP tracks manifold pressure/vacuum to pin down engine load, sharpen transient response, adjust spark and fuel under changing conditions, support altitude compensation, and validate readings for onboard diagnostics. If the MAF goes out of whack, the ECU can lean more on the MAP to keep the car drivable.

When the MAP sensor goes skew-whiff, owners may notice rough idle, sluggish take-off, flat spots on tip-in, higher fuel use, or the odd stall. Common fault codes include P0106 (MAP range/performance), P0107 (low input) and P0108 (high input).

While the MAP sensor isn’t a scheduled replacement item, it’s smart to give it some attention every 50,000–60,000 kilometres, or any time there’s a drivability gripe. That’s especially true if the car does lots of short trips or sees a fair bit of oil vapour through the intake.

• Inspect the connector for corrosion, broken locks or chafed wiring.
• Make sure the sensor’s O-ring seals cleanly to the manifold and isn’t flattened or nicked.
• If there’s light oily residue, a gentle spray of electronics-safe cleaner can help. Don’t poke the sensing port.

Replacement is straightforward under the bonnet:

1. Ignition off, let the engine cool.
2. Unclip the electrical connector.
3. Remove the retaining bolt/screw and ease the sensor out, don’t lever on the plastic.
4. Lightly oil a new O-ring, seat the new sensor squarely, and refit the hardware to factory snugness.
5. Reconnect the plug, clear any codes with a scan tool, and take a short drive so the ECU can settle trims.

For best results, stick with a quality OEM-grade sensor that matches the Subaru calibration. A quick health check with live data (KOEO and idle kPa readings) is a handy way to confirm the fix without any guesswork.

Does the 2019 Subaru Legacy use both a MAF and a MAP sensor?

Yes. The Legacy’s ECU uses the MAF for primary airflow measurement and the MAP to track manifold pressure for load, altitude compensation, transient response and diagnostics. It’s a belt-and-braces strategy that keeps fuelling tidy and drivability smooth.

Where is the MAP sensor on a 2019 Legacy, and what are the tell-tale failure signs?

It’s bolted to the intake manifold near the throttle body, under the engine cover. Symptoms include rough idle, hesitation on take-off, poor fuel economy, stalling, and codes like P0106, P0107 or P0108. Visual checks of the plug and O-ring, plus a scan of live kPa data, will point you in the right direction.

Can the MAP sensor be cleaned, or should it be replaced?

Light contamination can often be cleaned with electronics-safe cleaner. If readings remain out of range, the sensor is cracked, or faults return quickly, replacement is the go. Use an OEM-equivalent sensor and a fresh O-ring for a proper seal, then clear codes and road test.