GM 2.8L V6 ALDL

[Shawn R. Lin]

Peter Gargano wrote:
> 
> "Shawn R. Lin" wrote:
> >
> > I can get chatter from my '89 Olds Cutlass Supreme (2.8L V6 VIN W).
> 
> What does this "chatter" look like?

Here is just a clipping of the chatter (from CarBytes 2.0) yesterday:

Replay: $0A,$58,$00,$03,$92,$09
Replay: $0A,$58,$00,$03,$89,$12
Replay: $0A,$58,$00,$03,$8E,$0D
Replay: $0A,$58,$00,$03,$88,$13
Replay: $05,$5F,$00,$00,$00,$3C,$88,$FD,$16,$01,$A5,$A7,$78
Replay: $0A,$58,$00,$03,$85,$16
Replay: $0A,$58,$00,$03,$84,$17
Replay: $0A,$58,$00,$03,$74,$27
Replay: $0A,$58,$00,$03,$7C,$1F
Replay: $05,$5F,$00,$00,$00,$3C,$88,$FF,$44,$01,$A5,$A7,$48

This pattern (4 lines of $0A followed by 1 line of $05) repeats
continuously.
Today, after trying repeatedly to send what I believe to be the correct
Mode 1 string, the chatter changed.

Replay: $F0,$55,$BB
Replay: $0A,$58,$00,$03,$9C,$FF
Replay: $0A,$58,$00,$03,$97,$04
Replay: $0A,$58,$00,$03,$A4,$F7
Replay: $05,$5F,$00,$00,$00,$3C,$84,$32,$AD,$01,$A5,$9E,$B9
Replay: $0A,$58,$00,$03,$A2,$F9
Replay: $F0,$55,$BB
Replay: $0A,$58,$00,$03,$A0,$FB
Replay: $0A,$58,$00,$03,$A5,$F6
Replay: $0A,$58,$00,$03,$97,$04
Replay: $05,$5F,$00,$00,$00,$3C,$84,$35,$CF,$01,$A5,$9E,$94
Replay: $0A,$58,$00,$03,$97,$04

I don't know whre that $F0,$55,$BB came from.
However, the chatter is looking exactly like the protocol described on
Andy Whittaker's page for the Lotus Esprit.
http://www.andywhittaker.com/ecu/aldl.htm

> > However, I can't get it to spit out Mode 1 data (or any other mode for
> > that matter).  I've tried sending it the Mode 1 string for the Lotus
> > 4-cyl, '93 LT1 Camaro, and even tried sending it the string that's
> > preprogrammed into ScanTool.exe.  No luck.  Carbytes 2.0 shows that it
> > just echoes back.
> 
> The echo is (probably) from your interface, not the ECM.
> Most interfaces will echo back what is sent -  without the
> ECM doing anything.

Yes, I agree that the echo is probably from the interface.

> > For some reason, repeatedly transmitting the Mode 1
> > string for LT1 causes Carbytes 2.0 to lock up.  CTRL-ALT-DEL shows
> > "CarBytes [Not Responding]" and "MsgSrv32 [Not Responding]".
> 
> All ECM code that I've seen ignores frames that it doesn't
> accept, or it doesn't recognise, or has a bad checksum, or
> is transmitted when it's transmitting itself, etc.
> 
> It'll just sit there looking dumb until it get what it wants

I think the lockup was just a coincidence, but now I'm convinced my
interface won't transmit to the ALDL!  Now I guess I need to figure out
if my interface isn't working right or if it's a software prob, or???
Any ideas?

Shawn



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