- 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
.