Barometric Pressure Circuit Range/Performance

Possible causes

• CommonFailed barometric pressure sensor
• CommonCorroded connector or damaged wiring
• CommonSensor integral to the MAP sensor or the module, so a MAP fault presents here
• PossibleBlocked or split sensing passage
• PossibleLoss of reference voltage or earth

What you might notice

• Poor running at altitude, or after a change in altitude
• Rough idle or hesitation
• Worse fuel economy
• Black smoke on a diesel
• Check engine light on

What to check, in order

1. Compare the reported barometric pressure with the local weather reading, allowing for altitude. On a stationary engine with the ignition on, it should be close.
2. Compare it with the MAP sensor reading with the engine off - they should agree, because both are measuring the same still air.
3. Inspect the connector for corrosion and water.
4. Check the reference voltage and earth at the sensor.
5. On many vehicles this sensor is inside the MAP sensor or the control module, so check whether it is separately replaceable before ordering anything.