Engine Cooling Diagnostic System Check
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 left 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 Body Control Module (BCM) and Powertrain Control Module (PCM). If scan tool communicates with BCM and PCM, go to next step. If scan tool does not communicate with BCM and PCM, go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS.
- Using scan tool, select DISPLAY DTCS function. Retrieve and record any PCM DTCs and their status. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, repair engine cooling concern by symptom. See appropriate ENGINES article.
- If scan tool does not display any DTCs which begin with a "U", go to next step. 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.