Reading Diagnostic Trouble Codes DTC(s) With a Scan Tool
The IPC does NOT turn ON the SERVICE ENGINE SOON Malfunction Indicator
Lamp (MIL). The IPC turns ON various Telltales that are related to the malfunction
detected. The recommended method for reading DTC(s) stored in memory is by
using a scan tool plugged into the DLC connector (located under the instrument
panel on the left side). Follow the scan tool instructions supplied by the
tool manufacturer. The DTC(s) will be stored in the memory of the IPC as a
Current or a History DTC.
Current Codes
The IPC will set the code as a current DTC under the following conditions:
| • | The IPC determines that the test conditions and failure conditions
for a particular DTC are true. |
| • | A current ignition cycle occurs. |
All DTC(s) remain current until the following conditions exist:
| • | The next fault-free ignition cycle occurs. |
| • | The IPC determines that the test conditions are true. |
| • | The IPC determines that the failure conditions are false. |
The Current code then will become a History code only when the above
conditions exist.
History Codes
When a DTC reports a failure and the failure was not in the current
ignition cycle, the DTC will be stored as a history code. The IPC performs
internal diagnostic tests in order to acknowledge that the related systems
have reported a pass or fail condition. Each diagnostic test that fails is
recorded in the IPC memory. The IPC memory may be accessed with a scan tool
in order to determine which DTC circuit was at fault. A history DTC may be
cleared (for any diagnostic test) by performing any of the following procedures:
| • | Complete 100 subsequent ignition cycles with no diagnostic
test reporting a fail. |
| | Important: Disconnecting the battery or disconnecting the IPC connector will clear
all current and history IPC DTC(s).
|
| • | Disconnect the battery. |
| • | Disconnect the IPC connector. |
After Diagnosis is Complete
After diagnosing a problem, in addition to repairing the discovered
malfunction, clear any DTC(s) set and verify proper operation. In order to
verify proper operation, you must duplicate the conditions when the customer's
complaint occurred. If a DTC was set, you must duplicate the test conditions
for that DTC (listed on the facing page of the Diagnostic Trouble Code table)
and refer to conditions for setting the DTC. The DTC should not re-set after
the repair has been completed.
