Description
The purpose of this test is to satisfy the enable criteria necessary to execute 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. Ensure the vehicle meets the requirements listed in Conditions for Running before performing the EVAP System Test. Failure to meet the necessary requirements may produce inaccurate test results.
Conditions for Running
| • | The barometric pressure (BARO) is more than 75 kPa. |
| • | The engine coolant temperature (ECT) is 0-42°C (32-107°F). |
| • | The intake air temperature (IAT) is between 2-32°C (36-88°F). |
| • | The fuel level is between ¼ and ¾. |
| • | The battery voltage is between 11-16 volts. |
| • | The engine is in Closed Loop fuel control. |
| • | The vehicle has been driven for 10 minutes for at least 10 km (6 miles) and then the engine idles for 1.0 minute. |
Diagnostic Aids
| • | Extreme high or low ambient temperatures may prevent the EVAP system tests from initiating. Performing a visual inspection prior to running the EVAP Test may prevent having to repeat the test. A loose fuel cap may cause the test to abort or fail and prevent the I/M System Status from updating. A failed or aborted test will require the engine to cool down in order to meet the enable criteria to run another test. |
| • | The I/M System Status does not indicate whether the test has passed or failed, only that a decision was made. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the required tests have not run. When a failure occurs, the Emission Related DTC portion of the I/M System Status display will indicate the malfunction indicator lamp (MIL) is requested. The I/M System Status also registers the number of diagnostic trouble codes (DTCs). |
| • | The first failure of a type B DTC does not constitute a final determination of pass or fail, and will not update the I/M System Status to YES. A second and third trip is required, and all the conditions to run must be met in order for the test to run again. These conditions require a complete engine cool down before the EVAP I/M ready status changes to YES. |
| • | The I/M System Status will update only when an emission related DTC fails the second time, or when all of the tests pass. |
| • | 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 an A/C compressor clutch turning ON, may cause the test to abort. |
| • | If a diagnostic test is difficult to run, maintain necessary enable conditions until the system status updates to YES. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Make sure you perform the I/M system check before performing this test. Failure to do so may result in difficulty updating the status to YES.
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The engine coolant temperature must be less than 42°C (107°F) for the EVAP test to run. The ignition can be turned ON to monitor the engine coolant temperature with a scan tool, without starting the engine. This will determine if another test will run. This must be performed 3 times before going to the next portion of the EVAP test.
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This step is to identify a first failure of a type B DTC. A DTC only appears on the I/M System Status display when it 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.
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This step is to help 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.
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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.
Step | Action | Yes | No |
|---|---|---|---|
Did you perform the Inspection/Maintenance (I/M) System Check? | Go to Step 2 | ||
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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 lead to serious personal injury and vehicle damage.
Important: Once the engine is started, DO NOT turn OFF the engine for the remainder of the procedure until the test is complete. In order for this test to run, the vehicle must operate in the following conditions:Important: You can monitor the engine coolant temperature with the ignition ON and the engine OFF. The engine coolant temperature must be less than 42°C (107°F) to run another EVAP test. Important: To reset the EVAP I/M status, 2 additional cold starts are required. Did you complete the 3 cold starts? | Go to Step 3 | -- | |
3 |
Did the EVAP System Status update to YES? | Go to Step 6 | Go to Step 4 |
With a scan tool, observe the DTC Information. Does the scan tool indicate any failed DTCs? | Go to Step 5 | ||
Did the EVAP System Status update to YES? | Go to Step 6 | Go to Diagnostic Aids | |
With a scan tool, observe the Emission Related DTC portion of the I/M System Status display. Does the scan tool indicate any Emission Related DTCs set? | System OK |
