Automatic Transmission Diagnostic System Check
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2002 GMC Savana, 2002 Chevrolet Chevy Express, 2001 GMC Savana Special, 2001 GMC Savana Camper Special, and 2001 GMC Savana. 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 you have been directed to this table from another section in the service information. Do not turn ignition OFF when performing this diagnostic procedure. Do not clear DTCs unless instructed by this diagnostic procedure.
- Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC), located below steering column. Turn ignition switch to RUN position. If scan tool powers up, go to next step. If scan tool does not power up, go to TEST A: SCAN TOOL DOES NOT POWER UP under SYSTEM TESTS.
- If Malfunction Indication Light (MIL) is illuminated, go to next step. If MIL is not illuminated, repair MIL circuit as necessary. See ANALOG INSTRUMENT PANELS - CHEVY EXPRESS & SAVANA article.
- Using scan tool, attempt to communicate with Powertrain Control Module (PCM). If scan tool communicates with PCM, go to next step. If scan tool does not communicate with PCM, go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS.
- Select DISPLAY DTCs function on scan tool for PCM. If scan tool displays any DTCs, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not display any DTCs, repair by symptom. See appropriate ELECTRONIC CONTROLS in AUTOMATIC TRANSMISSIONS.