Barometric Pressure Sensor "A" Circuit Range/Performance

What it means

The barometric pressure (BARO) sensor is sending a signal that is electrically valid but does not make sense compared with other sensors. The barometric pressure (BARO) sensor measures outside air pressure, which changes with altitude and weather, for fuel and boost calculations. This usually points to a sensor that is reading wrong, or to a real mechanical problem it is reporting correctly, rather than a broken wire.

Symptoms

• Check engine light on
• Hesitation or poor power
• Rich or lean running at altitude

Probable causes

Most likely first

1. 1Reading not matching the MAP sensor with key on, engine off
2. 2Failing sensor giving an inaccurate reading
3. 3Poor connection at the sensor connector

How to diagnose it

Work through these in order before buying parts

1. 1Record the code and its freeze frame data (speed, load, temperature when it set), then clear it and see if it comes back.
2. 2Inspect the barometric pressure (BARO) sensor connector and wiring (inside the ECU or as a separate sensor in the engine bay). Look for corrosion, bent or pushed-back pins, oil contamination and chafed insulation.
3. 3Watch the barometric pressure (BARO) sensor reading on live data. Key on, engine off: BARO and MAP should read the same, roughly 100 kPa at sea level and less at altitude.
4. 4Compare the barometric pressure (BARO) sensor reading against related sensors and the real-world condition. If they disagree, find out which one is telling the truth before buying parts.
5. 5If the wiring checks out, test the sensor itself against the specification in a service manual.
6. 6Check for technical service bulletins (TSBs) or software updates for your make and model; some codes have known factory fixes.

Common fixes

• Fix the underlying problem the sensor is reporting, if real
• Replace the barometric pressure (BARO) sensor if it reads wrong against a known-good reference