- Powertrain/On-Board Diagnostic System Check

OBD System Check:

On-Board Diagnostic (OBD) System Check:

CIRCUIT DESCRIPTION
The on-board diagnostic system check is an organized approach to identifying a problem created by an electronic powertrain control system malfunction. It must be the starting point for any driveability complaint diagnosis, because it directs the service technician to the next logical step in diagnosing the complaint. Understanding the chart and using it correctly will reduce diagnostic time and prevent the unnecessary replacement of good parts.

TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.

1. This step is to determine if the Tech 1 can establish communication with the Powertrain Control Module (PCM). If it cannot, no data from the Data Link Connector (DLC) will be displayed on the Tech 1 scan tool.
2. This test is to determine if the PCM can control the Malfunction Indicator Lamp (MIL) using the MIL system check.

NOTE: This vehicle is equipped with a PCM utilizing an Electrically Erasable Programmable Read Only Memory (EEPROM). When diagnostics call for replacement of the PCM, the new PCM must be programmed. Refer to Computers and Controls / Powertrain Control Module / Service and Repair / Programming Procedures.