MAP/Barometric Pressure Circuit Range/Performance
The P0106 code indicates that the Engine Control Module (ECM) has detected an unexpected voltage or signal from the Manifold Absolute Pressure (MAP) sensor or Barometric Pressure (BARO) sensor. Specifically, the sensor's output does not correlate with the expected values based on current engine load, throttle position, and RPM.
While the vehicle can usually still be driven, a faulty MAP sensor disrupts the air-fuel mixture. This can lead to poor fuel economy, rough running, and potential long-term damage to the catalytic converter if left unaddressed.
Common symptoms
- Illuminated Check Engine Light
- Rough or unstable engine idle
- Engine hesitation or stumbling upon acceleration
- Decreased fuel efficiency
- Black smoke from the exhaust due to a rich fuel condition
Likely causes
- Vacuum leak in the intake manifold or associated hoses
- Defective or contaminated MAP sensor
- Corroded, damaged, or loose wiring and connectors in the MAP circuit
- Clogged or restricted MAP sensor vacuum port
- Faulty Barometric Pressure (BARO) sensor
- Engine mechanical issues causing abnormal intake vacuum (e.g., burned valves or timing issues)
What to check before replacing parts
Inspect all vacuum hoses connected to the intake manifold and MAP sensor.
Look for: Look for cracked, disconnected, collapsed, or brittle vacuum lines that could cause a vacuum leak and skew the sensor reading.
Visually inspect the MAP sensor wiring harness and connector.
Look for: Look for frayed wires, loose terminal pins, or green corrosion at the MAP sensor connector that could cause high resistance or an intermittent connection.
Monitor MAP sensor live data using an OBD-II scan tool.
Look for: Look for the MAP sensor voltage or pressure reading to change smoothly as the throttle is snapped open and closed; a static, sluggish, or erratic reading indicates a sensor or circuit fault.
Perform a mechanical vacuum test on the intake manifold using a vacuum gauge.
Look for: Look for a steady vacuum reading at idle (typically 17-21 inHg); a low or rapidly fluctuating reading points to a vacuum leak or mechanical engine issue rather than a bad sensor.
Test the MAP sensor circuit with a digital multimeter.
Look for: Look for a proper 5-volt reference signal and a good ground at the sensor connector with the key on, engine off; if either is missing, the issue lies in the wiring harness or ECM.
This page explains the generic P0106 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.
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