P0107 – Manifold Absolute Pressure (MAP) Sensor Circuit Low Input

The Diagnostic Trouble Code (DTC) P0107 indicates that the Engine Control Module (ECM/PCM) has detected a lower-than-expected voltage signal from the Manifold Absolute Pressure (MAP) sensor. This usually means the MAP sensor is reporting an abnormally low intake manifold pressure signal due to an electrical fault, vacuum issue, or sensor failure.

Symptoms

• Check Engine Light is illuminated.
• Hard starting.
• Rough or unstable idle.
• Poor engine performance.
• Reduced engine power.
• Engine hesitation.
• Possible engine stalling.

Possible Causes

• Faulty MAP sensor.
• Short to ground in the signal circuit.
• Open 5V reference circuit.
• Poor electrical connector.
• Damaged wiring harness.
• Blocked or damaged MAP vacuum hose (if equipped).
• Engine mechanical vacuum problem.
• ECM fault (rare).

Diagnostic Procedure

1. Read all stored and pending DTCs.
2. Inspect the MAP sensor connector for corrosion or loose terminals.
3. Verify the 5V reference, ground, and signal circuits.
4. Inspect the vacuum hose and intake manifold.
5. Check for damaged wiring or short-to-ground conditions.
6. Compare MAP readings with engine operating conditions.
7. Replace the MAP sensor only after confirming it has failed.

Live Data Diagnosis (Autel Scanner)

Using an Autel scan tool:

1. Select ECM → Live Data.
2. Monitor the MAP (kPa) parameter.
3. With the ignition ON and engine OFF, the MAP value should normally read approximately 95–101 kPa, depending on altitude.
4. At idle, most naturally aspirated gasoline engines typically read 25–40 kPa.
5. If the reading remains extremely low or near zero regardless of engine operation, inspect the sensor, wiring, and reference voltage.

Typical MAP Signal Path

Intake Manifold
       │
       ▼
   MAP Sensor
       │
     Signal
       ▼
    ECM / PCM
       │
Fuel & Ignition Control

Note: Wiring colors, connector pin assignments, voltage values, and vacuum hose routing differ between vehicle manufacturers. Always consult the appropriate wiring diagram for the specific vehicle.

Smoke Test

If a smoke machine is available, inspect the intake system for vacuum leaks.

• Inspect vacuum hoses.
• Check the intake manifold gasket.
• Inspect the throttle body gasket.
• Repair any leaks before replacing the MAP sensor.

Vacuum leaks can alter manifold pressure and contribute to MAP sensor-related diagnostic trouble codes.

Common Repairs

• Repair damaged wiring.
• Repair a short-to-ground condition.
• Restore the 5V reference circuit.
• Repair intake vacuum leaks.
• Replace the MAP sensor if testing confirms failure.

Important Note

P0107 does not always indicate a defective MAP sensor. Always verify the reference voltage, ground, wiring integrity, and live data before replacing the sensor.