The numbers below refer to the step numbers on the diagnostic table.
If powertrain related DTCs are present, there may be a powertrain performance condition present which could be a contributing cause to the customer concern.
This step is designed to identify engine-speed related disturbances that are NOT torque or load sensitive.
This step is designed to identify engine-speed related disturbances that ARE torque or load sensitive.
Making comparisons of the customer vehicle with an equally equipped, same model year and type, KNOWN GOOD vehicle will help determine if certain disturbances may be characteristic of a vehicle design.
Step | Action | Yes | No |
---|---|---|---|
Caution: Refer to Work Stall Test Caution in the Preface section. | |||
1 | Has the Vibration Analysis - Road Testing table been completed? | Go to Step 2 | |
Using a scan tool, determine if any DTCs are set. Were any DTCs set? | Go to Diagnostic Starting Point - Engine Controls in Engine Controls - 4.3L, or Diagnostic Starting Point - Engine Controls in Engine Controls - 4.8L, 5.3L, and 6.0L, or Diagnostic Starting Point - Engine Controls in Engine Controls - 6.6L (LLY), or Diagnostic Starting Point - Engine Controls in Engine Controls - 8.1L | Go to Step 3 | |
Were you able to duplicate the customer concern? | Go to Step 5 | Go to Step 4 | |
Were you able to duplicate the customer concern? | Go to Step 5 | ||
5 | Did the J 38792-A detect a dominant frequency? | Go to Step 6 | |
Compare the test results of the customer vehicle to the results of the same tests run, at the same engine RPM, on an equally-equipped, same model year and type, KNOWN GOOD vehicle. Refer to Vehicle-to-Vehicle Diagnostic Comparison .
Did both of the vehicles exhibit the same characteristics? |