What Does P0104 Mean?
The mass air flow sensor 'A' circuit is producing an intermittent or erratic signal. The PCM detects rapid, unexpected fluctuations in the MAF signal that don't correspond to actual changes in airflow. This often indicates a loose connection, damaged wiring, or a sensor that is failing intermittently. The driver may notice intermittent hesitation, surging, rough idle that comes and goes, or erratic fuel trim behavior.
Common Causes
35%
Loose, corroded, or intermittent MAF sensor connector
25%
Damaged or chafed wiring with intermittent contact
20%
Failing MAF sensor element with intermittent response
10%
Loose intake boot or air leak that opens and closes with engine vibration or temperature
10%
Electromagnetic interference from spark plug wires or ignition coil proximity
Diagnostic Steps
1
Monitor the MAF PID in live data graphing mode and watch for sudden spikes or dropouts — a stable signal should smoothly follow throttle input.
2
Perform a wiggle test on the MAF sensor connector and harness while watching the live data — any spike or dropout during wiggling pinpoints the fault location.
3
Inspect the MAF connector pins for signs of corrosion, green oxidation, or terminals that are spread and not making firm contact — repair or replace the connector as needed.
4
Check the wiring harness routing for any areas where the wires may chafe against sharp edges, exhaust components, or moving parts.
5
Clean the MAF sensor element — contamination can cause erratic readings as the hot wire struggles to maintain temperature with deposits on it.
Estimated Repair Cost
$20 - $350
Parts + labor, varies by vehicle and location
The mass air flow sensor 'A' circuit is producing an intermittent or erratic signal. The PCM detects rapid, unexpected fluctuations in the MAF signal that don't correspond to actual changes in airflow. This often indicates a loose connection, damaged wiring, or a sensor that is failing intermittentl...
The most common cause of P0104 (Mass or Volume Air Flow "A" Circuit Intermittent) is: Loose, corroded, or intermittent MAF sensor connector
Typical repair costs for P0104 range from $20 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive but with occasional drivability issues. The intermittent nature means the engine runs normally most of the time. However, if the signal drops out during acceleration, a momentary hesitation could be problematic in traffic. Diagnose at your convenience but don't ignore it long-term.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0104 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel / Air Metering System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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