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For 1990-2009 cars only
Makes 🢒 Buick 🢒 2004 🢒 Century 🢒 Engine 🢒 Engine Controls - 3.1L 🢒 Inspection/Maintenance Evaporative Emission System Set

Description

The purpose of this test is to satisfy the enable criteria necessary to execute inspection/maintenance (I/M) readiness diagnostics for the evaporative emission (EVAP) system. The test may be used to set the I/M System Status indicators to YES. The I/M System Status display on the scan tool indicates whether or not the control module has completed the required test. The required test is complete when either all of the DTCs comprising the test have run and passed, or when any one of the DTCs comprising the test has illuminated the malfunction indicator lamp (MIL). Once the test is complete, the I/M System Status display will indicate YES in the completed column. Performing a visual inspection prior to running the EVAP test may prevent having to repeat the test due to the fact that a failed or aborted test will require the vehicle to cool down in order to meet the enable criteria to run another test.

Conditions for Running
    • The barometric pressure is more than 75 kPa.
    • The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
    • The fuel level is between 15-85 percent.
    • The battery voltage is between 10-18 volts.
    • The intake air temperature (IAT) is between 4-30°C (39-86°F).
    • The startup ECT and IAT are within 8°C (14°F) of each other.
    • The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

Diagnostic Aids

Extreme high or low ambient temperatures may prevent the EVAP System Tests from initiating.

If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load such as a cooling fan or A/C compressor clutch turning ON may cause the test to abort.

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

Select Special Functions with a scan tool.

Does the Special Functions list include Service Bay Tests?

Go to Step 3

Go to Step 5

3

Perform the Service Bay Test. Refer to 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, e.g., 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. Ensure the vehicle is within the Conditions for Running as specified in the supporting text.
  2. Turn OFF all of the accessories, e.g., A/C, 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 the engine and idle for 2 minutes.

    4. Caution: Refer to Road Test Caution in the Preface section.

    Important: In order for this test to run, the vehicle must operate in the following conditions:

  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 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 evaporative emission (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. Refer to the Inspection/Maintenance (I/M) System DTC Table to determine which DTCs are required to run in order to complete this test.
  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, located in the supporting text for the diagnostic table of the DTC.
  6. Repeat the procedure until the scan tool indicates 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