P0109 - Manifold Absolute Pressure/Barometric Pressure Circuit Circuit Intermittent

The MAP or BARO sensor signal is cutting in and out intermittently.

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Code Overview

The MAP or BARO sensor signal is cutting in and out intermittently.

Common Causes

• Failing MAP or BARO sensor
• Damaged wiring or loose connector at the sensor
• Intermittent open or short in the circuit
• Loose vacuum source or sensor-port issue on applicable systems

Symptoms

• Intermittent hesitation or surge
• Unstable idle quality
• MAP or BARO readings that drop out unexpectedly

Diagnostic Steps

1. Wiggle-test the MAP or BARO connector and harness while watching scan data
2. Verify reference voltage, ground, and signal integrity at the sensor
3. Compare scan data to a realistic barometric or load-related reading
4. Inspect the vacuum hose or sensor port if the system uses one

Repair Difficulty

Moderate

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