[Zalan]

Does anyone know how the SPA module in the trunk 'knows' that the car is in reverse?
What signal is sent to it and how?

 

[jvanabra]

Gear position is present on the (P?) bus... I would assume that way!

 

[okcrum]

Yes, message comes from UEC or TCM on P-bus, depending on transmission, and gets routed to SPA on I-bus by CIM.

 

[Zalan]

Thanks guys. Is it a PWM signal of what parameters? or do you know anything more ?

 

[okcrum]

It's a CAN bus message.

 

[Zalan]

Yes; I'm asking for the electrical components of it and I presume it's coded a string of 1s and 0s.
So let's leave that aspect and if you can help me out with this question, I would appreciate it:
I have recently installed SPA on a car that never had it. I expected to see something in the SID to say it needed to be added with a Tech2 but nothing appeared. Is this normal? Is there any way to tell that the SPA system is OK but just needs the Tech2 employed to add it?

 

[jvanabra]

Until the module has been coded to the CAN bus with Tech 2 the system has no way of knowing it's there... That's why it must be programmed, that's how CAN works.

 

[okcrum]

After adding with Tech 2 you also have to enable it in the Settings (SID). Two separate operations.

 

[Zalan]

Got it. Thanks. Now I just have to employ a Tech2, which won't be cheap even if I can find one.
In hindsight, my adding the OEM SPA seems a bit silly when you can get a Reversing alarm (complete with sensors and buzzer) for less than $20

 

[okcrum]

True, but the $20 alarm doesn't tell you instructions for turning. Tech 2 clone is $300 or you can check Tech 2 forum to see if there's someone nearby with one who can do the add for you.

 

[Zalan]

I appreciate your responses in this thread. You have now piqued my interest (I have had my Saab only a few months): what do these "instructions for turning' consist of. And do they come with a 2005 9-3 ?
Thanks - Alan

 

[okcrum]

The range info clues you in on when to turn. Newer cars give trajectory hints via software change. Now that we finally know what car you have, you get audible alerts with thresholds of 3 ft. and 1 ft. There are plenty of videos about installing, enabling, and operation of the system.

 

[Zalan]

Roger, Over and out.