Possible Causes
WARNING: This page is about a different car, the 2003 Toyota Tacoma. However, it is still accessible from the selected car via links, so may be relevant.
DTC is set when ECM detects MAF meter output is greater than 2.2 volts with engine coolant temperature of 158°F (70°C) and throttle valve closed with engine speed of 900 RPM or less for more than 10 seconds, or when MAF meter output is less than 0.25 volt Throttle Position (TP) sensor VTA circuit signal voltage is 0.1 volt or more with engine speed of 1850 RPM or more for more than 10 seconds. Possible cause is defective MAF meter.