Cruise Control Diagnostic System Check
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:
The presence of DTCs which begin with "U" indicate some other module on Class 2 serial data line is not communicating.
- Connect scan tool to Data Link Connector (DLC). DLC is located under driver side of instrument panel. 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.
- Turn ignition switch to RUN position. 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.
- Using scan tool, select DISPLAY DTCS function and retrieve any PCM DTCs. If scan tool does not display any cruise control DTCs, go to next step. If scan tool displays any cruise control DTCs, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
- If scan tool displays any DTCs which begin with a "U", go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS. If scan tool displays any other DTCs, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not display any DTCs diagnose cruise control by symptom. See SYSTEM TESTS in CRUISE CONTROL SYSTEMS - ALERO & GRAND AM article.