PGM-FI System Description - On-Board Snapshot
Overview
To facilitate the diagnosis of "engine stalls" or "engine hard to start" troubleshooting, the PCM records the on-board snapshot of the driving conditions (parameters) when the trouble occurs. This on-board snapshot is exclusively used for "engine stalls" or "engine hard to start".
There are three kinds of the on-board snapshot:
- On-board snapshot when DTC is stored
- On-board snapshot when engine stalls
- On-board snapshot when engine does not start
The recorded parameters of the on-board snapshot in the PCM can be confirmed by the HDS. Since the PCM can record only the first on-board snapshot, it is necessary to delete the snapshot when a check is finished.
Control
On-board snapshot when engine stalls:
The precondition to record the on-board snapshot for engine stalls is as follows. If the engine stalls at this precondition, the PCM records the parameters related to the engine stall for a total of 10 seconds (9 seconds before the engine stall occurrence, and 1 second after the occurrence).
The precondition is:
- 5 seconds has elapsed after the engine is started (engine RPM is 500 RPM or more)
- Engine speed when the engine stalled is less than 3, 000 RPM
On-board snapshot when engine does not start:
On-board snapshots for engine that do not start are divided into the following three kinds:
- Engine does not start (long cranking time but does not start)
- Engine is hard to start (needs time to start)
- Engine starts but stalls immediately
On-board snapshot of "engine will not start" and "engine is hard to start":
If the cranking (engine speed is less than 500 RPM) time is longer than the specified time (time varies depends on the condition when the engine starting), and judged as hard to start, the PCM records the parameters related to the hard to start for a total of 10 seconds (9 seconds before judging, and 1 second after it).
"Engine will not start"
"Engine is hard to start"
On-board snapshot of "engine starts but stalls immediately":
If the engine starts normally but stalls within 5 seconds afterward, the PCM records the parameters related to the engine stall for a total of 10 seconds (9 seconds before engine stalls, and 1 second after it).
"Engine starts but stalls immediately"