Signal Function

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Ford RV Cutaway, 2006 Ford Pickup, 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.

The MAF sensor measures the airflow rate into the engine and provides an analog signal to the powertrain control module (PCM) which is used to calculate air flow for the exhaust gas. recirculation (EGR) monitor.

The current PCM implementation contains a mass airflow interface, which consists of a 2-pole, differential input, low pass filter. This filter is designed to pass an analog signal, originating from the mass air sensor, while rejecting unwanted ignition noise, high frequency electrical interference, and ground offsets.

The input to the interface is the analog voltage signal difference between MAF+ (mass airflow signal) and MAF- (mass airflow return). The MAF sensor output an analog voltage signal calibrated to 0.5 V at the lower limit of the flow range and 4.75 V at the upper limit of the flow range.

The intake air temperature (IAT) is also integrated into the MAF sensor.

This pinpoint test is intended to diagnose the following:

MAF sensor
harness circuits: MAF SIG, MAF RTN, vehicle power (VPWR), and power ground (PWRGND)
PCM

Fig 1: Mass Air Flow/Intake Air Temperature (MAF/IAT) Sensor Connector

Fig 2: Powertrain Control Module (PCM) Connectors