Circuit/System Verification
- 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
- Any vacuum leak
- Water intrusion
- Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust .
- 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 2-6 g/s at idle to 100 g/s or more at the time of the 1-2 shift.
- A steady or intermittent high resistance of 15 ohms or more on the ignition 1 voltage circuit will cause the MAF sensor values to be skewed high by up to 60 g/s. Use the scan tool and compare the MAF Sensor parameter to a known good vehicle, under various operating conditions.
- A skewed or stuck engine coolant temperature (ECT) or intake air temperature (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 barometric pressure (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 and compare the BARO parameter at ignition ON to the Altitude vs. Barometric Pressure table. 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 and compare the MAP Sensor parameter to a known good vehicle, under various operating conditions.