The purpose of this procedure is to satisfy the enable criteria necessary to execute inspection/maintenance (I/M) readiness diagnostics for the heated oxygen sensor (HO2S) heater system. This procedure may be used to set the HO2S Heater I/m System Status display on the scan tool to YES. The HO2S Heater I/M System Status display indicates whether or not the control module has completed the readiness diagnostics. The readiness diagnostics complete when all DTCs comprising the diagnostics run and pass, or any DTC comprising the diagnostics illuminates the malfunction indicator lamp (MIL). Once the diagnostics complete, the HO2S Heater I/M System Status display will be updated to YES.
• | The engine coolant temperature (ECT) is more than 70°C (158°F). |
• | The battery voltage is between 10-18 volts. |
If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the system set procedure. If DTCs do not run and no DTC is set, review the appropriated scan tool data list and service information. This will give an indication of why the DTCs do not run. Some diagnostics may abort due to changes in the conditions while the diagnostics are running. For example, changes in engine load such as a cooling fan or A/C compressor clutch turning ON, may cause the diagnostics to abort. If the HO2S Heater I/M System Status does not update to YES, the procedure can be repeated until a YES status is achieved.
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 6 | Go to Step 3 |
3 |
Caution: Refer to Road Test Caution in the Preface section. Important: If the heated oxygen sensor (HO2S) Heater inspection/maintenance (I/M) System Status updates to YES at any time during the drive procedure, disregard the remaining numbers in this step.
Did the HO2S Heater System Status update to YES? | 2 minutes | Go to Step 6 | Go to Step 4 |
4 | Observe the DTC information with a scan tool. Does the scan tool indicate any failed DTCs? | -- | Go to Step 5 | |
5 |
Did the HO2S Heater System Status update to YES? | -- | Go to Step 6 | Go to Diagnostic Aids |
6 | 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 |