Forcing Speed-Density Mode on a GM Vehicle

When modifying a VE table, it is necessary to temporarily force the vehicle into speed-density mode so that the effect of your changes can be accurately observed in VCM Scanner.

NOTE: This procedure involves changing parameters whose original values will need to be restored later. Make note of the initial value of each parameter before you change it.

Follow these steps.

1. Navigate to Engine > Airflow > Dynamic.
2. Set High RPM Disable to an rpm value higher than the engine will reach. (8000 is usually good)
3. Navigate to Engine Diagnostics > Airflow.
4. Set MAF Frequency Fail High to 0 Hz.
5. Some GM trucks will also have two parameters named High Count Thresh and Low Count Thresh in the Mass Airflow Sensor group. If you see these parameters, set them both to 0.
6. Navigate to Engine Diagnostics > DTCs.
7. Change the Error Mode for codes P0101, P0102, and P0103 to MIL on First Error.