[Diy_efi] PCM/ECM wish list question

Steve Ravet Steve.Ravet
Sun Dec 31 06:30:01 UTC 2006


 

> -----Original Message-----
> From: diy_efi-bounces at diy-efi.org 
> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Steven P. Donegan
> Sent: Saturday, December 30, 2006 9:01 AM
> To: diy_efi at diy-efi.org
> Subject: Re: [Diy_efi] PCM/ECM wish list question
> 
> Thank you for the feedback. What do the Main relay driver and 
> the SES lamp driver actually do? I had not thought of OBDII 
> at all as the system talks via RS-232 already. I suppose to 
> make it a complete plug-compatable unit OBDII will be 
> required. I have no intention of feeding any data to the 
> car's black box (ie the air bag controller) other than that 
> required for the air bags to function.

The airbag and any other boxes in the car (anti theft?  body control
module?) will expect to communicate over the OBD2 bus with the engine
computer.  How the computer talks to diagnostic equipment is up to you,
but if you include OBD2 (GM's version of OBD2 is called VPW) in your
computer then maybe it makes sense to use it for diagnostics and
reflashing as well.  There is a VPW interface chip from motorola that is
pretty easy to use, I'm working on a project right now that uses it.

Not sure about main relay, but SES is the driver for the service engine
soon light.  In your computer you might be able to put back the "use SES
to blink out error codes" function that was deleted when OBD2 came
along.

--steve






More information about the Diy_efi mailing list