Circuit Description

This test determines if MAF sensor is providing proper readings to the PCM. MAF sensor is a high frequency device that measures the rate of airflow through the throttle body. MAF sensor outputs a series of pulses that varies in frequency with airflow. PCM uses this signal for fuel control.

MAF sensor readings during acceleration will be much higher than those during deceleration or idle. PCM calculates what MAF sensor reading should be from the sensor under certain conditions using engine speed (RPM), throttle position, and altitude parameters. When certain test conditions are met, PCM will compare its calculated MAF value to the actual value received from the sensor. The calculated MAF reading is calculated by comparing MAP, RPM and IAT values. If difference between calculated MAF and actual MAF is too great, DTC P0101 will set.

For duplication of DTC, ensure:

• Other DTCs are not set.
• System voltage is 11-16 volts.
• System is in "closed loop" fuel control.
• Canister purge duty cycle is less than or equal to 99.6 percent.
• EGR rescaled pintle position is less than or equal to 240 counts.
• Traction control is not active.
• TP sensor angle is 50 percent or less.
• 100 msec delta MAP is 5 kPa or less.