Diagnostic System Check - Engine Cooling

Install a scan tool. Does the scan tool power up? If so, go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article under ACCESSORIES & EQUIPMENT.
NOTE: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
Turn ON the ignition, with the engine OFF. Attempt to establish communication with the following control modules:
- Instrument Cluster
- Powertrain Control Module
Does the scan tool communicate with the control modules? If so, go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article under ACCESSORIES & EQUIPMENT.
NOTE: Determine if the Instrument Cluster or Powertrain Control Modules have set DTCs which may affect Engine Cooling operation are present.
Select the POWERTRAIN CONTROL MODULE display DTCs function on the scan tool. Does the scan tool display any DTCs? If so, go to next step. If not, go to SYMPTOMS - ENGINE COOLING under TROUBLE SHOOTING.
NOTE: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
Does the scan tool display any DTCs which begin with a "U"? If so, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article under ACCESSORIES & EQUIPMENT. If not, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS .