GM > Engine Diagnostics > Airflow

MAF Sensor

• MAF Sensor Fail High: This is the frequency threshold at which the VCM will set the High MAF Frequency DTC (P0103)
• MAF Sensor Fail Low: This is the frequency threshold at which the VCM will set the Low MAF Frequency DTC (P0102)
• MAF Test ERT Min: This is the minimum engine run time before the MAF frequency tests will run.
• MAF Test IGNV Min: Ignition voltage must be above this before the MAF frequency tests will run.
• MAF Test RPM Min: RPM must be above this before the MAF frequency tests will run.
• MAF Test Enable Delay: Once the above thresholds are met this delay must expire before the MAF frequency tests will begin.
• MAF Test High Count Thresh: Number of times the MAF frequency must be high before P0103 will set.
• MAF Test Low Count Thresh: Number of times the MAF frequency must be low before P0102 will set.

  
  

• Maximum Delta Air Flow - P0101 Error: The VCM will constantly check the MAF operation by comparing the MAF calculated airflow against the calculated airflow using speed/density calculations. If the difference exceeds the threshold value at the particular speed/density calculated airflow then P0101 will be set.

MAP Sensor
The VCM calculates a predicted MAP signal based on current TPS and RPM. If the measured MAP is out of range then P0106 is set. This can be a problem for supercharged vehicles.

• P0106 MAP Test Max: This table specifies the maximum MAP predicted based on TPS and RPM.
• P0106 MAP Test Min: This table specifies the minimum MAP predicted based on TPS and RPM.

MAP Sensor Calibration
Change these values if you change the MAP sensor (in conjunction with 2 (or 3) bar code).

• MAP Sensor Calibration Linear: The linear calibration of the MAP sensor (slope)
• MAP Sensor Calibration Linear B: The linear calibration of the MAP sensor (slope) (if specified should be set to 1/3 of the above calibration).
• MAP Sensor Calibration Offset: The offset calibration of the MAP sensor