ISO9141

[xxalexx at ix.netcom.com]

> From:          martin at mgass.demon.co.uk
> To:            diy_efi at efi332.eng.ohio-state.edu
> Date:          Tue, 10 Mar 1998 16:01:50 +0000
> Subject:       ISO9141
> Priority:      normal
> Reply-to:      diy_efi at efi332.eng.ohio-state.edu

> Anybody able to throw more light on the initiation sequences of the 
> above protocol.
> 
> Using a VB4 Program I am montoring comms between a laptop with 
> a ScanTool on it and the J1962 connector.  I also have a VB4 
> program emulating an ECU (connected straight to scantool using rs232).
> 
> I know the theory about grounding the K or L line or both (or tx a one 
> byte address at 5 bps). And the ECU replying with 55h at specified baud 
> rate.
> 
> At the moment I see the scan tool do the following (at rs232 level)
> -Change CTS
> -Change RI
> -Send Break
> It then reponds to a Break sent back to it.
> 
> What is the next sequences in the protocol ?

wait for vehicle keywords.

> 
> I know about ISO-9141-2 etc, but don't have a copy just yet.
> 
> I am particulalrly interested in any deviations from the Spec for 
> European GM Vehicles.

US GM uses J2190 data packets which not a open standard. 

alex