P0103
Medium SeverityMass Air Flow Sensor Circuit High Input
Fuel System
P0103 — Instant Answer
Mass Air Flow Sensor Circuit High Input
Severity: MEDIUM SEVERITY
Meaning: The MAF sensor is reading higher than expected airflow. This causes the engine to run rich. Could be a sensor fault or an intake leak.
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $40 - $150
Most common causes:
- 1. Faulty MAF sensor (35-45% of cases)
- 2. Short circuit in MAF wiring (10-25% of cases)
- 3. Air leak in intake boot (10-25% of cases)
- 4. Aftermarket air filter issue (10-25% of cases)
Symptoms
- ⚠️Rich running (black exhaust)
- ⚠️Poor fuel economy
- ⚠️Check engine light
- ⚠️Rough idle
Related Symptoms
Common Causes
How to Diagnose P0103
- 1Inspect MAF sensor connector
- 2Check intake duct for cracks
- 3Clean MAF sensor
- 4Test MAF output with scan tool
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0103.
Related Symptoms
Browse →A check-engine light is a graph entry point into code pages, symptom-specific diagnosis, and the exact repair categories most often associated with those failures.
Rough idle often traces back to ignition, air metering, vacuum leaks, or timing-related faults before it becomes a full misfire complaint.
Exact Vehicle Hubs
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Open the exact vehicle hub for a repair workflow commonly associated with P0103.
Open the exact vehicle hub for a repair workflow commonly associated with P0103.
Open the exact vehicle hub for a repair workflow commonly associated with P0103.
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Open the exact repair flow most commonly associated with P0103 on this vehicle.
Open the exact repair flow most commonly associated with P0103 on this vehicle.
Open the exact repair flow most commonly associated with P0103 on this vehicle.
Open the exact repair flow most commonly associated with P0103 on this vehicle.
Related Codes
The MAF sensor is reading outside the expected range for current engine conditions. Could be dirty, defective, or have an air leak after the sensor.
The MAF sensor is reporting lower airflow than expected. The engine thinks less air is entering than actually is, causing a lean condition.
Bank 1 is running rich — too much fuel relative to air. The ECM cannot trim enough fuel out to compensate.
Frequently Asked Questions
- What causes P0103?
- Usually a failed MAF sensor or a short in the sensor wiring. Sometimes caused by an oiled aftermarket air filter contaminating the sensor element.
- Can an oiled air filter cause P0103?
- Yes — oiled aftermarket filters (like some K&N filters) can contaminate the MAF sensor wire, causing false high readings.
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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