I am having problems creating a datastream defintion file. The datastream is A140, for a 1991 3.1L Cavalier. I can get Tunerpro to connect but not display the info from the ECM. I am assuming my first command, Mode 8, is working as the ALDL connects. After that things get a little fuzzy. Here's some snipets from the A140 spec file, Quote: The ECM is the master of ALDL. When an ALDL tester is useto gather ALDL data, it should gain master ship of ALDL by issuing a mode 8 to the ECM. Once the tester has gained mastership, it's testers responsibility to schedule and command normal mode (see normal mode message schedule) from the ECM to maintain normal system functionality while gathering ALDL data from any module on the data link. Quote: MODE 7 (COMMAND NORMAL MODE MESSAGE) ALDL REQUEST: - MESSAGE ID = $F4 - MESSAGE LENGTH = $57 - MODE = $07 - ECM SCHEDULER MESSAGE CODE ($05, $0A, $F0) - SUM CHECK THE ECM WILL RESPOND WITH THE APPROPRIATE NORMAL MODE SCHEDULER MESSAGE IF ONE EXISTS FOR THAT PARTICULAR SCHEDULER MESSAGE CODE." Quote: NORMAL MODE MESSAGE SCHEDULE ---------------------------- MASTER MODULE NORMAL MODE MESSAGES TO BE COMMANDED DURING MODE 1, 2, 3, & 4 COMMUNICATIONS WITH ANY CONTROLLER ON THE DATA LINK. THESE MESSAGES ARE TO BE COMMANDED WITH A MODE 7 COMMAND TO THE MASTER. COMMAND ID LISTEN ID MES LENGTH $0A $0A x ECM BROADCAST MESSAGE $05 $05 x ECM BROADCAST MESSAGE COMMAND ID: THIS IS THE ID OF THE NORMAL MODE MESSAGE TO BE COMMANDED BY A MODE 7 TO THE MASTER. LISTEN ID : WHEN THE MODE 7 IS SENT TO THE MASTER, THE MASTER TRANSMITS THE REQUESTED NORMAL MODE MESSAGE WHICH MAY OR MAY NOT CAUSE A RESPONSE MESSAGE TO BE GENERATED BY ANOTHER MODULE. IN ORDER TO MAINTAIN PROPER SYNCHRONIZATION WITH TRAFFIC ON THE DATA LINK, THE LISTEN ID SHOULD BE THAT OF THE RESPONSE MESSAGE IF ONE IS GENERATED OR THE COMMAND ID IF NO RESPONSE IS GENERATED BY THE NORMAL MODE MESSAGE. MES LENGTH: IF THE RESPONSE MESSAGE ID IS THE SAME AS THE COMMANDED MESSAGE ID THE MESSAGE LENGTH IS USED TO DIFFERENTIATE THE RESPONSE MESSAGE FROM THE TRANSMIT MESSAGE." From what I can gather I need to command Mode 7, Command String: F4, 57, 07, F0 and the ECM should respond with the Mode 1 Data Stream. Payload size: 63, Offset 4. I have tried a bunch of different combination and commanding Mode7 and Mode 1 at different times. Nothing seems to work. Any ideas? I have used freescan, in the status window it commands Mode 8 then Mode 1 and everything works without the Mode 7 stuff. I have tried it in Tunerpro without success. Thank You for any help, Steve

No, you send a Mode 1 command to receive a mode 1 message.

Mode 7 restarts the chatter that you stopped with the Mode 8 command.

Fix that first. If you're still having trouble:

After it connects, is the error count increasing? If so, while the error count climbs, manually send the mode 8 commands until the error count stops climbing. If you can get that to happen, you should be getting data.

This will all be better after I re-write the ALDL engine.

M

Ok thanks Magnus. Just to confirm, I do not need mode 7. Mode 8 first, then Mode 1 to get Data.

Error counts stays at zero when it connects at first. Count goes up by 1 if I send Mode 1 command. I will have to play around some more when I get home.

Thanks
Steve

Correct, you shouldn't need the Mode 7 command. You *may* not need the mode 8 command either. That depends on whether or not your ECM/BCC is "chatty".

M

I pretty sure I need Mode 8. The it will only connect if I send the Mode 8 first. Also Freescan has to send Mode 8 first before the Mode 1.

Thanks
Steve

Ok, so I was able to play around with it some more tonight. Unfortunaltey I am still at square one.

I did notice something a little strange. Here's what I am doing;
-Mode 8 first, aldl connects, no data.
-Send Mode 1 command, I get 1 Packet error, only 1 not multiple like chatter.
-Send Mode 8 Command, no error, no data. However F456 appears as my Prom ID. F4, 56 are the first two bits of my Mode 8 command. So it appears the ECM does not want to send the Mode 1 data for some reason.

Here are my command settings

Mode 8 (first command on list)
Command String: F4, 56, 08
Payload Size: 3 bytes
Payload Offset: 1
Checksum Cmd

Mode 1 (second on list)
Command String: F4, 57, 01
Payload Size: 63 Bytes
payload Offset: 4
Monitor
(I also tried Checksum Cmd on/off with no effect)

This is what the A140 specs say, maybe an error there?
Thank you for any help,
Steve

The F456 you're seeing is the echo of the mode 8 command (F4 56 08 checksum).

Do this:

Hit connect, let it connect with no data. Send a bunch of mode 8 commands (just keep sending them with the "send command" button) until you start getting data.

See if that works.

Unfortunately you have a chatty ECM. I'll be doing the re-write over the next couple of months, after which this will no longer be a problem. Sorry about that!

Mark

Haha, I don't think there is any need to be sorry I have received more support with this "free" program, then any commercial program. I will try it and let you know what happens.

Thank you for all your help.
Steve

Nothing happened Sent Mode 8 a million times, still same thing. I tried sending a bunch of the other modes to see what kind of errors I could get and what worked. No combination could get data to transmit.

I am kind of suprised none of the DIY guys here have ever tried hooking an aldl cable up to a Cavalier (91-94 that is). There were probably more Z24 V6 cars made then all the Camaros.

Thanks again,
Steve

Only need to send the mode 1 commands. Once the ECM recognizes one it will respond with the data and wait for another command. The chatter will stop for a period of time. As long as you keep sending mode 1's the ECM will keep responding with data.

I am kind of suprised none of the DIY guys here have ever tried hooking an aldl cable up to a Cavalier (91-94 that is).

Maybe because this is a 3rd-gen f-body site?

RBob.

Yes this is a 3rd gen site Thought somebody would own a z24 winter beater like me.

Mode 1 by it's self will not allow the ALDL to connect. Freescan has a status window where you can see the commands sent to the ECM and the response. Mode 1 causes chatter, Mode 8 stops the chatter, then allows Mode 1 transmit the data as normal.

Thanks again.
Steve

Yes, I believe there is an error there. For the Mode 1 command send F4, 56, 01 instead of F4, 57, 01. When I did my .ads for the $0D mask, I had to do this and all was fine. For some reason, a lot of the datastream definitions have this command wrong. HTH

I think I may have tried F4,56, 01 already, but I'll try it again incase I missed it.

Thanks
Steve