Mode 8 and Mode 9 for LT5?

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colinb
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Joined: Sun Mar 15, 2015 5:49 am

Mode 8 and Mode 9 for LT5?

Post by colinb »

Do certain GM engines/ECMs not support certain ALDL modes? I'm looking at the data stream spec documents, and it seems like none of the LT5 engines (from the ZR-1 Corvette) list Mode 8 or Mode 9 commands.

I'm very new to working with ALDL, but does this mean that the LT5 does not require a Mode 8 command to stop chatter? Does anyone know how the ECM will respond if given a mode command that it doesn't support?

I'm experimenting with the linuxaldl utility, which is just a proof-of-concept program that does not support ADX files. I've found that the linuxaldl code always tries to send a Mode 8 command before getting Mode 1 data. Maybe this is unnecessary?

--Colin
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dex
The Ford Guy
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Joined: Thu Oct 07, 2004 6:38 am

Post by dex »

Not all ALDL modes are supported in some ECM's. The $74 mask I'm currently looking at only supports Mode 0, 1, 2, 3, 4, 7 and 10 requests.

In this ecu responding to the F97 ALDL polling message is sufficient to stop the "normal mode" broadcast messages. The "normal mode" broadcast messages are then inhibited for as long as activity is seen on the ALDL network. Either 5 seconds of network inactivity or a Mode 0 request starts the "normal mode" broadcast messages again.
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