Circuit Description

WARNING: This page is about a different car, the 2002 Pontiac Grand Am and 2002 Oldsmobile Alero. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Check for applicable service bulletins before proceeding with this test. Perform this test only if there is a driveability complaint or if directed to this table from another article.

Poor engine performance can sometimes be diagnosed as a transaxle driveability condition. To avoid incorrect diagnosis of automatic transaxle, always perform POWERTRAIN CONTROL MODULE DIAGNOSTIC SYSTEM CHECK (2.2L) or POWERTRAIN CONTROL MODULE DIAGNOSTIC SYSTEM CHECK (3.4L) before diagnosing transaxle. Automatic transaxle diagnostic system check is an organized approach to identify a problem created by an automatic transaxle. Automatic transaxle diagnostic system check is diagnostic starting point for an automatic transaxle complaint. Automatic transaxle diagnostic system check points to next logical step for diagnosing a transaxle concern. Perform this check only if there is a driveability complaint or if directed here from another service procedure.

Follow testing procedure to help reduce diagnostic time and help prevent unnecessary replacement of good parts. Use a scan tool that is known to function correctly. If necessary, test scan tool on another vehicle. Ensure scan tool contains most current software updates available. Scan tool will display a loss of communication error message under following conditions:

PCM power is interrupted
Ignition switch is turned to OFF position
Battery voltage level is very low
Poor connection at Diagnostic Link Connector (DLC)