P0107 OBD2 Code Guide
P0107 is a sensors diagnostic trouble code. Use this hub to understand the plain meaning, the first checks to run, and which vehicle-specific guides may be more useful before replacing parts.
MAP/Barometric Pressure Circuit Low Input
Code P0107 indicates that the Powertrain Control Module (PCM) has detected a voltage signal from the Manifold Absolute Pressure (MAP) sensor that is abnormally low, falling below the manufacturer's specified threshold for current engine operating conditions. A low voltage signal from the MAP sensor typically suggests either an extremely high manifold vacuum (which is unusual under normal circumstances for a fault code) or, more commonly, an electrical fault within the MAP sensor itself or its associated wiring circuit, such as a short to ground or an open circuit in the reference voltage or signal line. This incorrect input can lead to the PCM miscalculating fuel delivery and ignition timing, resulting in various drivability issues.
Code verification standard
P0107 is published with SAE J2012 / ISO 15031-6 code structure plus OBD2 P0107 diagnostic context.
First checks
- - Read all stored and pending codes before clearing anything.
- - Save freeze-frame data so you know speed, load and temperature when the code set.
- - Inspect wiring, connectors, fuses, hoses and obvious leaks tied to the named system.
- - Compare live data against realistic values before buying sensors or modules.
- - Clear the code only after repair and complete a drive cycle to confirm it does not return.
P0107 diagnostic path
- 11. **Visual Inspection of MAP Sensor and Circuit**: Carefully inspect the MAP sensor's electrical connector for any signs of corrosion, bent pins, or loose connections. Trace the wiring harness back from the sensor for any visible damage, chafing, or signs of a short to ground. Also, inspect the vacuum hose (if applicable) connecting the MAP sensor to the intake manifold for cracks, kinks, or disconnections.
- 22. **Scan Tool Data Analysis**: Connect a diagnostic scan tool and monitor the MAP sensor voltage and pressure readings (kPa or inHg) with the ignition key on, engine off (KOEO). The pressure reading should be very close to the ambient barometric pressure. Start the engine and observe the MAP sensor voltage and pressure at idle. A P0107 indicates the voltage is consistently below the expected threshold, even at KOEO or idle, suggesting a sensor or circuit fault. Compare these readings to manufacturer specifications.
- 33. **Electrical Circuit Integrity Test**: Disconnect the MAP sensor and use a multimeter to test the wiring harness connector. Verify the presence of a stable 5-volt reference signal and a good ground connection. Then, back-probe the signal wire with the sensor connected and the engine running, observing the voltage output. Compare this live voltage to the vehicle's service manual specifications for various engine conditions. A short to ground in the signal wire or an open circuit in the reference/ground wire can cause a low input.
- 44. **MAP Sensor Performance Verification**: If all wiring and power supply tests pass, and the scan tool still shows an abnormally low voltage from the MAP sensor, the sensor itself is likely faulty. You can sometimes test the sensor's response to varying vacuum using a hand-held vacuum pump, observing the voltage change. If the voltage does not change proportionally with vacuum, or remains stuck low, the sensor needs replacement.
Verify before repair
- - Replace the faulty Manifold Absolute Pressure (MAP) sensor.
- - Repair or replace damaged wiring or connectors in the MAP sensor circuit (e.g., short to ground, open circuit in signal, reference, or ground wire).
- - Clear any obstructions or repair leaks in the MAP sensor's vacuum line (if applicable).
- - Diagnose and repair any underlying engine vacuum issues that might be causing an actual excessive vacuum condition (less common for P0107, but possible).
Vehicle-specific pages to check next
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