Enhanced diagnostic information is found in the History
Data function of the scan tool. Enhanced diagnostic information provides the
service technician with specific malfunction occurrence information.
The following occurs for each of the last 3 diagnostic trouble
codes stored:
| • | Data is stored to identify the specific DTC. |
| • | The number of occurrences for the DTC are stored. |
| • | The number of drive cycles since the malfunction first and last
occurred are stored. A drive cycle occurs when the engine is started. |
| • | The drive cycle counter will increment by starting the engine
and then turning the ignition OFF. |
| • | The scan tool also displays the following data display parameters
(if equipped): |
| - | Extended Travel Brake Switch |
| - | Lateral Accelerometer Input |
| • | The last 3 diagnostic trouble codes are stored in the order
of occurrence. |
In difficult diagnostic situations use the above information to identify
malfunction occurrence trends. Ask question such as the following:
| • | Did the malfunction only occur once over a large number of drive
cycles, indicating an unusual condition present when it occurred? |
| • | Does the malfunction occur infrequently over a large number of
drive cycles, indicating that special diagnostic techniques may be required
to identify the source of the malfunction? |
A malfunction that occurs more frequently increases the odds of finding
the cause of the malfunction.
Use the additional malfunction data to determine if a malfunction is
randomly intermittent. Use the additional malfunction data to determine if
it has not recurred for long periods of time due to weather changes
or a repair prior to this visit.
