P0107: Manifold Absolute Pressure Sensor Low Input

What it means

The MAP sensor reports a pressure below the lower threshold the ECU expects at any engine state. Typically indicates a hard electrical fault rather than a slow drift.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The MAP sensor measures intake manifold pressure and sends a signal the ECM uses to calculate engine load. P0107 sets when that signal falls below the expected electrical or pressure-signal threshold, commonly because the signal is grounded or the sensor reference supply is missing.

Common causes

Most likely first.

1. Signal wire shorted to ground
2. MAP sensor failed
3. 5V reference voltage missing

Symptoms

• Check engine light on

How to diagnose it

1. Review freeze-frame and live MAP data at key-on engine-off and at idle to confirm the reading is abnormally low or fixed.
2. Inspect the MAP connector and harness for a loose plug, corrosion, crushed insulation, or a wire touching ground.
3. Using the wiring diagram, check the sensor reference supply and ground against the manufacturer's specification before testing the signal wire.
4. Test the signal wire for a short to ground and check continuity between the sensor and ECM as directed by the manufacturer's procedure.
5. Inspect any MAP hose and sensor port for disconnection or blockage, which can affect the reported pressure.
6. If the reference, ground, wiring, and pressure path are correct, test the MAP sensor output and replace it if it remains below specification.

Common fixes

• Reconnect or repair a loose or corroded MAP connector.
• Repair a signal wire shorted to ground or other damaged harness section.
• Restore the missing sensor reference supply by repairing the confirmed wiring fault.
• Reconnect a detached MAP hose or clear a blocked sensor port, where fitted.
• Replace a MAP sensor that fails output checks with a sound circuit.

Can I keep driving?

Avoid long trips and heavy acceleration because the ECM may have to estimate engine load, which can cause poor running or stalling. Stop if the engine stalls or becomes difficult to control.