Mass Air Flow (MAF) Circuit Low Input
How does a P0102 code trigger the check engine light? The engine light will come on if the following concern is present:
The Mass Air Flow Sensor circuit is monitored by the powertrain control module (computer), for low voltage (which translates to low air flow) through the Comprehensive Component Monitor (CCM). With the key on and engine running, if the voltage drops below a minimum value this code will be set, causing the check engine light to illuminate.
MAF Sensor disconnected
MAF Sensor circuit open to computer
Vehicle Power circuit open to MAF Sensor
Power Ground circuit open to MAF Sensor
MAF Sensor Return circuit open to PCM
MAF Sensor circuit shorted to Ground
Intake air leak near MAF Sensor
Damaged MAF Sensor
Refer to an appropriate manual for specification. If MAF Sensor voltage reading is below minimum limit with key on engine running then concern is a hard fault (present now). If all values are in spec proceed with intermittent diagnosis (refer to our “Intermittent Diagnosis Help” article through the “articles” link on the Navigation Bar). You may also use the “Get Help” link if you need specifications or have any other related questions.
Mass Air Flow (MAF) Sensor
How does a P0100 code trigger the check engine light? This code will trigger the check engine light under the following conditions:
1. The computer receives an excessively high voltage from the MAF Sensor with the engine not running.
2. The computer receives an excessively low voltage from the MAF Sensor with the engine running.
3. The computer receives a high voltage reading from the MAF Sensor under light-load driving conditions.
MAF Sensor circuit open or shorted
Intake air leaks (unmetered air after MAF Sensor)
Defective MAF Sensor
Electronic Control Module (ECM)/Powertrian Control Module (PCM) concern
Monitor MAF Sensor voltage reading while increasing engine RPM. The MAF Sensor value should increase in proportion to engine speed. If not, first check for air leaks at intake tube, manifold and all vacuum lines. Then test the MAF Sensor circuits for opens and shorts. See our article Automotive Circuit Testing 101, if you need more assistance with this. If concern is determined to be intermittent, wiggle test connectors and wiring to attempt to duplicate concern. You may also use the “Get Help” link if you need specifications or have any other related questions. Remember to refer to an appropriate manual for specific instruction.