Accumulating Powertrain Control Module (PCM) Data

PCM data can be accumulated in a number of ways. Gather as much data as possible when the concern is occurring to prevent misdiagnosis. Data should be accumulated during different operating conditions and based on the customer description of the intermittent concern. Reference the known good data values located in Typical Diagnostic Reference Values  . This requires recording data in 4 conditions for comparison: 1) Key On Engine Off (KOEO), 2) Hot Idle, 3) 48 km/h (30 mph), and 4) 89 km/h (55 mph). Acquisition of PCM PID data using a scan tool is one of the easiest ways to gather information.

For information on the functions of your scan tool, refer to the manufacturer's article.

Below is a list of the functions available:

• selecting and viewing PIDs

• storing PIDs
• recording measurements along with PIDs
• playback of stored PIDs
• peripheral inputs