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Home >> Buick >> 2004 >> Century Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 153 (Engine Controls (Troubleshooting & Diagnosis) - 3.8L) >> Troubleshooting >> Inspection/Maintenance (I/M) Evaporative Emission (EVAP) System Set Procedure >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 1:  Perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES.
  2. 3:  This step determines whether or not the EVAP System Test has passed. If the system is operating correctly, the scan tool indicates that the system has passed and the I/M System Status updates to YES. If the EVAP Service Bay Test aborts because of lost enable conditions, the test can be repeated once the enable criteria is met.
  3. 4:  A failed DTC during the EVAP Service Bay Test may not appear in the DTC Information display on some vehicles. The Service Bay Test displays an indication of which test failed as a directive to the appropriate service information. Some vehicles will display the test as aborted and the first failure of type B DTC appears in the DTC Information.
  4. 5:  The EVAP System Test usually begins when the engine coolant temperature is between 4-30° C (39-86° F). The vehicle should be operated moderately until this temperature is reached. The engine coolant temperature can be monitored using the scan tool.
  5. 6:  This step identifies a first failure of a type B DTC. A DTC only appears on the I/M System Status display when the DTC becomes a MIL illuminating DTC. This occurs on the second failure of a type B DTC. A first failure of a type B DTC will not allow the I/M System Status to update to YES. Refer to Diagnostic Aids.
  6. 7:  This step helps to identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. This information is located in the service information under Conditions for Running the DTC.
  7. 8:  The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.
Inspection/Maintenance (I/M) Evaporative Emission (EVAP) System Set Procedure

Step Action Yes No
1  Did you perform the Inspection/Maintenance (I/M) System Check? Go to Step 2  Go to Inspection/Maintenance (I/M) System Check 
2
  1. Select Special Functions with a scan tool.
  2. Determine if the vehicle is equipped with a Service Bay Test for the EVAP System.
Is the vehicle equipped with EVAP Service Bay Test?		 Go to Step 3  Go to Step 5 
3 
  1. Verify that the vehicle is within the Conditions for Running.
  2. Turn OFF all of the accessories, such as the A/C, the blower fan, etc.
  3. Following the directions on the scan tool, perform the EVAP Service Bay Test.
Did the EVAP System pass the Service Bay Test?		 Go to Step 8  Go to Step 4 
4 
  1. Observe the scan tool Service Bay Test for an indication of why the test did not pass, such as failed DTC, test aborted, etc.
  2. Refer to the appropriate service information for diagnosis and repair of the condition as necessary.
Did you complete the repair?		 Go to Inspection/Maintenance (I/M) Complete System Set Procedure  -
5 
  1. Verify that the vehicle is within the Conditions for Running.
  2. Turn OFF all of the accessories, such as the A/C, the blower fan, etc.
    3. IMPORTANT: Once the engine is started, DO NOT turn the engine OFF for the remainder of the procedure until the test is complete.
  3. Start and idle the engine.
    4. CAUTION: Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could result in serious personal injury and vehicle damage.
    IMPORTANT: The vehicle must operate within the following conditions in order for this test to run:
  4. Acceleration at part throttle to 72 km/h (45 mph) with this speed maintained until the engine reaches operating temperature. This may be up to 8-10 minutes depending on the start up coolant temperature.
  5. Continue the operating conditions for an additional 3 minutes after the engine reaches operating temperature, or until the I/M System Status indicator updates to YES.
Did the EVAP System Status update to YES?		 Go to Step 8  Go to Step 6 
6  Observe the DTC Information with a scan tool.
Does the scan tool indicate any failed DTCs?		 Go to Diagnostic Trouble Code (DTC) List Go to Step 7 
7 
  1. Determine which DTCs are required to run in order to complete this test. Refer to Inspection/Maintenance (I/M) System DTC Table .
  2. Observe the Not Ran Since Code Cleared display with a scan tool.
  3. Determine which of the DTCs required for a YES status has not run.
  4. Enter the DTC number in the Specific DTC menu of the scan tool.
  5. Operate the vehicle within the Conditions for Running the DTC.
  6. Repeat the procedure until the scan tool indicates that the diagnostic test has run.
  7. Repeat steps 4-6 for any additional required DTCs that have not run.
  8. Observe the I/M System Status display with a scan tool.
Did the EVAP System Status update to YES?		 Go to Step 8  Go to Diagnostic Aids
8  Observe the Emission Related DTC portion of the I/M System Status display with a scan tool.
Does the scan tool indicate any Emission Related DTCs set?		 Go to Diagnostic Trouble Code (DTC) List System OK
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