Diagnostic Aids

• Inspect the harness of the mass air flow (MAF) sensor to verify that it is not routed too close to the following components:
  • The secondary ignition wires or coils
  • Any solenoids
  • Any relays
  • Any motors
• A low minimum air rate through the sensor bore at idle or during deceleration may cause this DTC to set. Inspect for the following conditions:
  • Any deposits on the throttle plate or in the throttle bore
  • Any vacuum leak downstream of the MAF sensor
• Inspect for any contamination or debris on the sensing elements of the MAF sensor.
• Inspect the air induction system for any water intrusion. Any water that reaches the MAF sensor will skew the sensor and may cause this DTC to set.
• 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 5-12 g/s at idle to 200 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.
• Inspect for a skewed or stuck ECT sensor.
• A high resistance of 15 ohms or more on the ignition 1 voltage circuit may cause the DTC to set. A high resistance may cause a driveability concern before this DTC sets.
• The barometric pressure that is used to calculate the predicted mass air flow value is initially based on the manifold absolute pressure (MAP) sensor at key ON. When the engine is running the BARO value is continually updated near wide open throttle. A skewed MAP sensor will cause the calculated mass air flow value to be inaccurate and may result in a no start condition. The value shown for the MAP sensor parameter varies with the altitude. With the ignition ON and the engine OFF, 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 may cause this DTC to set.
• A short to voltage on the 5-volt reference circuit of the MAP sensor may cause this DTC to set.

If the condition is intermittent, refer to Testing for Intermittent Conditions and Poor Connections .