P0104

Mass or Volume Air Flow Circuit Intermittent

Severity: Medium
Driving: Drivable — book it in

The mass airflow sensor signal is intermittent - it works, then drops out, then returns. Intermittent faults are almost always connections rather than components, because a failed sensor tends to stay failed.

Possible causes

CommonLoose or corroded connector at the sensor
CommonChafed wiring shorting intermittently against the engine or bodywork
PossibleFailing sensor breaking down when hot

What you might notice

Intermittent hesitation or surging
Occasional rough idle that comes and goes
Check engine light that appears and clears
Fault often worse over rough roads

What to check, in order

Unplug and inspect the connector. Look for spread terminals, corrosion, and a latch that does not click home.
With the engine idling, gently flex the harness near the sensor and watch the live airflow reading for a drop-out.
Trace the harness for chafing where it passes brackets or the engine.
Because the fault is intermittent, fix the connection first and re-test before replacing the sensor.

Read this code from your own car

Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.

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Where this code sits

B · Body C · Chassis P · Powertrain U · Network and communication