GM 2.8L V6 ALDL

[Shawn R. Lin]

Scot Sealander wrote:
> 
> "Shawn R. Lin" wrote:
> >
> > I can get chatter from my '89 Olds Cutlass Supreme (2.8L V6 VIN W).
> > 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.
> 
> I am not surprised it did not respond to that... Try sending it
> 
> "F0 58 01 CS"  where CS is the checksum.  It should respond to that.

Thanks Scot,
Maybe the checksum calculated by Carbytes 2.0 is wrong, and that's the
problem?

When I tried sending $F0,$58,$01, it automatically calculated the
checksum as $B9.
If I try sending $F0,$58,$01,$CS, it changes the string to
$F0,$57,$01,$00,$B8.

Also when I tried sending $F0,$56,$01, it calculates the checksum as $B9
as well.

What's the formula for manually computing checksums?

Shawn



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