Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 3: 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.
- 4: Determine if the Instrument Cluster or Powertrain Control Modules have set DTCs which may affect Engine Cooling operation are present.
- 5: 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.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review a Diagnostic Starting Point-Engine Cooling? | Go to Step 2 | Go to DIAGNOSTIC STARTING POINT - Engine Cooling |
| 2 | Install a scan tool. Does the scan tool power up? | Go to Step 3 | Go to SCAN TOOL DOES NOT POWER UP |
| 3 | Turn ON the ignition, with the engine OFF. Attempt to establish communication with the following control modules: The instrument cluster The powertrain control module Does the scan tool communicate with the control modules? | Go to Step 4 | Go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE |
| 4 | Select the powertrain control module display DTCs function on the scan tool. Does the scan tool display any DTCs? | Go to Step 5 | Go to SYMPTOMS - Engine Cooling |
| 5 | Does the scan tool display any DTCs which begin with a "U"? | Go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE | Go to Step 6 |
| 6 | Does the scan tool display any DTCs that are associated with the Engine Cooling System? | Go to Diagnostic Trouble Code (DTC) List | Go to SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L or SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS |
Diagnostic System Check - Engine Cooling