P0108
Medium SeverityMAP/BARO Sensor Circuit High Input
Fuel System
P0108 — Instant Answer
MAP/BARO Sensor Circuit High Input
Severity: MEDIUM SEVERITY
Meaning: MAP sensor voltage is higher than maximum expected range. The ECM reads this as very low vacuum.
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $20 - $80
Most common causes:
- 1. Faulty MAP sensor (35-45% of cases)
- 2. Open circuit in signal wire (10-25% of cases)
- 3. Large vacuum leak (10-25% of cases)
- 4. Damaged connector (10-25% of cases)
Symptoms
- ⚠️Rich running
- ⚠️Loss of power
- ⚠️Surging at idle
- ⚠️Black exhaust smoke
Common Causes
How to Diagnose P0108
- 1Check MAP sensor connector
- 2Measure sensor output voltage with KOEO
- 3Check signal wire for open circuit
- 4Replace sensor if stuck high
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The MAP (Manifold Absolute Pressure) sensor is reading outside normal range. Affects fuel delivery and ignition timing calculations.
MAP sensor voltage is below the expected minimum. The ECM sees this as extremely high vacuum, causing incorrect fuel calculations.
Frequently Asked Questions
- Can a vacuum leak cause P0108?
- Yes, a large vacuum leak can cause MAP readings to stay high (near atmospheric pressure), triggering P0108.
- How do I test a MAP sensor?
- With ignition on, MAP sensor should read about 4.5V at atmospheric pressure and drop to 1-2V at idle vacuum.
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Author & Review
Written by AllOEMManuals Editorial Team. Reviewed by ASE-certified technicians and updated with factory-reference checks for fitment-sensitive steps.
This guide was drafted with AI assistance and reviewed for accuracy by a human editor.
Last updated: 2026-05-07