Circuit/System Verification

Verify the integrity of the entire air induction system by inspecting for the following conditions:
- Any damaged components
- Loose or improper installation
- An air flow restriction
- An air flow leak
- Any vacuum leak
- In cold climates, inspect for any snow or ice buildup
- Water intrusion
Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust .

CAUTION: Refer to Road Test Caution .

Road test the vehicle and verify that the MAF sensor calculated g/s and the actual MAF g/s parameters are near or equal to each other.
A skewed MAF sensor, intake air flow restriction or intake air flow leak after the MAF sensor may cause the calculated g/s and MAF g/s parameters to disagree. Road test the vehicle while observing both parameters under various engine loads.
A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 3-8 g/s at idle to 190 g/s or more at the time of the 1-2 shift.
The BARO that is used by the ECM to calculate the air flow models is initially based on the MAP sensor at ignition ON. When the engine is running, the ECM will continually update the BARO value near WOT using the MAP sensor and a calculation. A skewed MAP sensor will cause the BARO value to be inaccurate. Use the scan tool to compare the BARO parameter at ignition ON to the Altitude vs. Barometric Pressure table. Determine the altitude for your area and refer to Altitude Versus Barometric Pressure .