Analyzing PCM Data

Look for abnormal events or values that are clearly incorrect. Inspect the signals for abrupt or unexpected changes. For example, during a steady cruise most of the sensor values should be relatively stable. Sensors such as mass air flow (MAF) and RPM that change abruptly when the vehicle is traveling at a constant speed are clues to a possible concern area.

Look for an agreement in related signals. For example, if the APP1, or APP2, changes during acceleration, a corresponding change should occur in RPM, fuel volume regulator (F_VCV) and fuel rate (FUELRATE) PIDs.

Scroll through the PID data while analyzing the information. Look for sudden drops or spikes in the values.