For 1990-2009 cars

### Description

The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the exhaust gas recirculation (EGR) 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 this test. Failure to meet the necessary requirements may produce inaccurate test results.

### Conditions for Running

• | The barometric pressure is more than 65 kPa.

• | Engine coolant is at operating temperature, 80-110°C (176-230°F).

• | The intake air temperature (IAT) is less than 65°C (149°F).

### Diagnostic Aids

The control module only runs the EGR Active Tests during a gradual deceleration with a closed throttle and a vehicle speed above 40 km/h (25 mph). Several deceleration cycles may be necessary in order to accumulate a sufficient number of EGR flow samples. The procedure outlined in the table is for a clear, flat road. If the procedure is performed on a road with a slight down hill grade, the test may acquire the necessary sample counters in one or two decel trips. If the test is interrupted during the procedure, it may take more than three deceleration cycles to complete the test. If the status does not update, the test outlined in this procedure can be repeated until the I/M System Status updates to YES.

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 updates to YES. If a test for a specific system has failed, the I/M System Status updates 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 indicates 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 trip is required, and all the conditions to run must be met in order for the test to run again. These conditions may include a partial to complete engine cool down.

The I/M System Status updates only when the DTC fails the second time, or 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 A/C compressor clutch turning ON may cause the test to abort.

If a diagnostic test is difficult to run, observe the I/M System Status display while maintaining the necessary enable conditions until the system status updates to YES.

### Test Description

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

1. 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.

2. The EGR Active Tests are run during a gradual deceleration with a closed throttle. The vehicle speed is required in order to maintain a high, steady manifold absolute pressure (MAP) signal.

3. 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.

4. 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.

5. 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
--- | --- | --- | ---
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. Ensure the vehicle is within the Conditions for Running specified in the supporting text.
2. Turn OFF all of the accessories, e.g., A/C, blower fan, etc.
3. Start the engine and allow it to idle.

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 for 1 minute.
5. Four decelerations of 25 seconds each from 72 km/h (45 mph) while the following criteria is maintained:

• | Throttle is closed

• | NO brake application

• | NO manual downshift

• | Vehicle speed remains above 40 km/h (25 mph)

• | After each deceleration period, vehicle is returned to 72 km/h (45 mph) under part throttle acceleration and speed is maintained for 15 seconds

6. With a scan tool, observe the I/M System Status display.

Did the EGR System Status update to YES?

Go to Step 5

Go to Step 3

3 | With a scan tool, observe the DTC Information. Does the scan tool indicate any failed DTCs? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 4
4 |

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. With a scan tool, observe the Not Ran Since Code Cleared display.
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. With a scan tool, observe the I/M System Status display.

Did the EGR System Status update to YES?

Go to Step 5

Go to Diagnostic Aids

5 | 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? | Go to Diagnostic Trouble Code (DTC) List | System OK