Emissions Related DTCs
Action Taken When the DTC Sets - Type A
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
Action Taken When the DTC Sets - Type B
The control module illuminates the MIL on the second or third consecutive ignition cycle that the diagnostic runs and fails.
Action Taken When the DTC Sets - Type B1
| • | The following applies to misfire DTCs: |
| - | If the control module detects a low level or an emission level misfire condition during 2 consecutive trips, the control module illuminates the MIL. |
| - | If the control module detects a high level or catalyst damaging misfire, the control module flashes the MIL at a rate of once per second. |
| - | If the control module detects a misfire during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur: |
| • | The engine load is within 10 percent of the previous test that failed. |
| • | The engine speed is within 375 RPM of the previous test that failed. |
| • | The engine coolant temperature is in the same range of the previous test that failed. |
| • | The following applies to fuel trim DTCs: |
| - | If the control module detects a fuel trim condition during 2 consecutive trips, the control module illuminates the MIL. |
| - | If the control module detects a fuel trim condition during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur: |
| • | The engine load is within 10 percent of the previous test that failed. |
| • | The engine speed is within 375 RPM of the previous test that failed. |
| • | The engine coolant temperature is in the same range of the previous test that failed. |
Conditions for Clearing the MIL/DTC - Type A or Type B
| • | The control module turns OFF the MIL after 3 or 4 consecutive ignition cycles, when the diagnostic runs and passes. |
| • | An active DTC clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL and the DTC. |
Non-Emissions Related DTCs
Action Taken When the DTC Sets - Type C
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The MIL will not illuminate. |
| • | The driver information center, if equipped, may display a message. |
Conditions for Clearing the DTC - Type C
| • | A last test failed, or active DTC, clears when the diagnostic runs and passes. |
| • | Use a scan tool in order to clear the DTC. |
Type X
No actions occur with a type X DTC. These DTCs are coded into the control modules software, but the DTC will not run because one of the following reasons:
| • | The associated hardware is not installed with the vehicles emission package. |
| • | The diagnostic is not required for the vehicles emission package. |
