MAP/Barometric Pressure Circuit Low Input
The Powertrain Control Module (PCM) has detected a voltage signal from the Manifold Absolute Pressure (MAP) sensor or Barometric Pressure (BARO) sensor that is below the expected minimum threshold, typically under 0.5 volts. This abnormally low input prevents the engine computer from accurately calculating engine load and adjusting the air-fuel mixture.
While the vehicle can usually still be driven, a faulty MAP sensor disrupts the air-fuel ratio. This can lead to poor drivability, stalling, and potential long-term damage to the catalytic converter if left unaddressed.
Common symptoms
- Illuminated Check Engine Light
- Rough idling or engine hesitation
- Poor fuel economy
- Engine stalling or difficulty starting
- Black smoke from the tailpipe under acceleration
Likely causes
- Defective MAP or Barometric Pressure sensor
- Damaged, shorted, or corroded wiring in the MAP sensor circuit
- Poor electrical connection at the MAP sensor connector
- Vacuum leak at the intake manifold or MAP sensor hose
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Inspect the MAP sensor wiring and connector.
Look for: Look for frayed wires, corrosion, or a loose connector that could cause a short to ground or an open circuit.
Check for vacuum leaks around the intake manifold and MAP sensor.
Look for: Listen for hissing sounds or use a smoke machine to find cracked hoses or leaking gaskets that would cause abnormal pressure readings.
Test the MAP sensor reference voltage with a multimeter.
Look for: With the key on and engine off, the reference wire should show approximately 5 volts. A reading of 0 volts indicates a wiring or PCM issue.
Measure the MAP sensor signal voltage.
Look for: The signal voltage should change smoothly as vacuum is applied using a hand vacuum pump. If the voltage remains stuck below 0.5 volts, the sensor is likely internally shorted.
Check the MAP sensor ground circuit.
Look for: Perform a voltage drop test or continuity test on the ground wire. High resistance indicates a poor ground connection causing signal issues.
This page explains the generic P0107 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
Gear guide: Best OBD2 ScannersRead this code yourself next time — from $20 Bluetooth dongles to bidirectional scan tools.Rather have a pro handle it? Find a vetted local mechanic.