Circuit/System Verification

IMPORTANT: If you cannot duplicate the condition, operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Verify the integrity of the 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
- 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.
A steady or intermittent high resistance of 25 ohms or more on the ignition 1 voltage circuit will cause the MAF sensor values to be skewed high by up to 30 g/s. Use the scan tool to compare the MAF Sensor parameter to a known good vehicle under various operating conditions.
A skewed or stuck engine coolant temperature (ECT) or IAT sensor will cause the calculated models to be inaccurate and may cause this DTC to run when it should not. Refer to Temperature vs Resistance .
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 vs Barometric Pressure .
A skewed MAP sensor will also cause the first and second intake manifold models to disagree with the actual MAP sensor measurements. Use the scan tool to compare the MAP Sensor parameter to a known good vehicle under various operating conditions.