Description
The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the heated oxygen sensor (HO2S) system. The test may be used to set the I/M System Status to YES. The I/M System Status display on the scan tool provides an indication of whether the control module has completed the required tests. the I/M System Status does not indicate that the tests have passed or failed. 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 other tests for that system have not run.
Conditions for Running
HO2S Bank 1 Sensor 1 and Bank 2 Sensor 1
| • | The engine speed is between 500-3,000 RPM. |
| • | The engine run time is less than 3 minutes. |
| • | The mass air flow (MAF) is between 4-30 g/s. |
| • | The battery voltage is between 9-18 volts. |
HO2S Bank 1 Sensor 2
| • | The engine cold start is determined. |
| • | The average MAF during warm-up is less than 30 g/s. |
| • | The battery voltage is between 10-18 volts. |
Diagnostic Aids
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.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Inspection/Maintenance (I/M) System Check? | -- | Go to Step 2 | |
2 |
Important: Whenever the ignition is turned ON, ignition positive voltage is supplied to the HO2S heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. Did the HO2S Heater System Status update to YES? | 2 minutes | Go to Step 5 | Go to Step 3 |
3 | Observe the DTC information with a scan tool. Does the scan tool indicate any failed DTCs? | -- | Go to Step 4 | |
4 |
Did the HO2S Heater System Status update to YES? | -- | Go to Step 5 | Go to Diagnostic Aids |
5 | 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? | -- | System OK |
