Accumulating PCM Data

Powertrain Control Module (PCM) data can be accumulated in a number of ways. Gather as much data as possible when the malfunction is occurring to prevent misdiagnosis. Data should be accumulated during different operating conditions and based on the customer description of the intermittent fault. Reference the known good data values. See Powertrain Management / Computers and Control Systems / Testing and Inspection / Procedures / Diagnostic Charts (Pinpoint Tests) / Z - Intermittent/Diagnostic Reference Value Charts. Normal Scan Data Values - Includes Pids

This will require recording data in four conditions for comparison:

1. Key On Engine Off (KOEO),

2. HOT IDLE,

3. 30 MPH

4. 55 MPH.

Acquisition of PCM PID data using a scan tool is one of the easiest ways to gather information.