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Diagnostic Aids
- Inspect the harness of the MAF sensor to verify that it is not routed too close to the following components:
- A wide open throttle acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 3-6 g/s at idle to 140 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
- 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 shouldn't.
- 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 and may cause this DTC to set. A high resistance will cause a driveability concern before this DTC sets.
- The BARO that is used by the PCM to calculate the air flow models is initially based on the MAP sensor at key ON. When the engine is running, the PCM will continually update the BARO value near wide open throttle using the MAP sensor and a calculation. A skewed MAP sensor will cause the calculated mass air flow value to be inaccurate and may result in a no start condition. With the ignition ON and the engine OFF, the MAP Sensor parameter varies with the altitude. 101 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
- A high resistance on the low reference circuit of the MAP sensor will skew the sensor value and may cause this DTC to set.
- If the condition is intermittent, refer to Testing for Intermittent Conditions and Poor Connections
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