Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Lack of communication may be due to a partial or total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
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The presence of DTCs indicates that the PCM or TAC has detected a fault.
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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.
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This step insures that the PTO options in the scan tool are set according to the upfitters recommendations.
Step | Action | Yes | No |
|---|---|---|---|
1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | Go to Scan Tool Does Not Power Up in Data Link Communications |
Does the scan tool communicate with both of these control modules? | Go to Step 3 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | |
Select the display DTCs function on the scan tool. Does the scan tool display any PCM or TAC DTCs? | Go to Step 4 | Go to Step 5 | |
Does the scan tool display any DTCs which begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Diagnostic Starting Point - Engine Controls in Engine Controls or Diagnostic Starting Point - Cruise Control in Cruise Control | |
View the PTO options on the scan tool to verify that the PTO settings are correct for the specific PTO application. Are the PTO settings correct? | Go to Step 6 | ||
6 | Change the PTO options as needed. See upfitter specifications in the upfitter installation manual. Are the PTO options set correctly? | -- |
