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 located in the Diagnostic Reference Value Charts.

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 Parameter Identification (PID) data using a scan tool is one of the easiest ways to gather information.

NOTE: Listed below are instructions for gathering PID data using a New Generation STAR (NGS) scan tool.

SELECTING AND VIEWING PIDs
1. Select VEHICLE & ENGINE SELECTION and enter the proper year, vehicle and engine package from the menu.
2. Select DIAGNOSTIC DATA LINK.
3. Select POWERTRAIN CONTROL MODULE (PCM).
4. Select GENERIC OBD II FUNCTIONS.
5. Select the PIDs from the intermittent symptom chart or the PCM Pinpoint test. The star symbol next to each PID on the screen indicates that PID has been selected.
6. Turn ignition key ON or start vehicle.
7. Select the START key and access the PIDs.

PERIPHERAL INPUTS
Some signals may require certain peripherals or auxiliary tools to aid in diagnostics. In some cases, these devices can be inserted into the measurement jacks of the NGS or Digital Volt-Ohm Multimeter (DVOM). The NGS is capable of recording the value from the measurement jacks on the NGS while storing the value from other PIDs. For example, connecting an electronic fuel pressure gauge to monitor and record the fuel pressure voltage reading, and capturing the data, would help find the fault. Listed are two types of peripheral devices available.
- Multi-Point Auxiliary Adapter - A/C, Fuel Pump (Rotunda 007-00023 or equivalent)
- Electronic Fuel Pressure/Vacuum Adapter - Fuel Pressure, Vacuum (Rotunda 007-00022 or equivalent)