CASIS doesn't work
 

This may seem trivial, but the shift indicator on my tach doesn't work 100% of the time. I have only seen it work 3 times for only a few minutes since I bought the car a year ago. I have gone through the WSM procedures for diagnosis. Since the coolant temp gauge, speedo and tach all work, I am assuming that those signals are getting to the cluster just fine (and speedo and temp signals should therefore make it to the tach's internal computer). I tested for the presence of the injection timing signal at the cluster and it is present. There is continuity present on this wire all the way to the tach's computer circuit board. I know it's not important for it to work, but if possible I would like to fix it. At night (way too dim to see during day) I noticed that the upshift indicator arrow lights up with the key in pos II and stays lit until the key is turned off. I am not sure if the tach does a bulb check during power-on or not, or if the internal computer is junk. Any suggestion? I will not be replacing the tach if the computer is bad.

so what is a SISAC?

I believe it stands for Computer Aided/assisted/automated Shift Indicator System (according to the car's owners manual). Just a fancy name for the upshift light in the dash.

Wow, the acronym doesn't even match the definition. Well, unless your dyslexic.

Oh i thought it was a System Indicator Shift Assist Computer

Didn't you just ask what it stood for a couple posts up?

Anyways, I think it's

Speed
Is
So
Awesomely
Cool

no, I read the OP`s question in a mirror

Check the 14 pin connector above the hot post for corrosion, and the speedometer connections in the tire well

speedo works, so I should be getting that signal to the tach. I will recheck the 14 pin connector though. Has anyone ever been able to diagnose/fix the tach internals?

Hi :)

WHAT upshift light ???

Is this something that American 928s got that Euros didnt ?

My tach has no shift up lights ???

All the best Brett :)

Yes, it is only available in US cars with 5spd transmission

Hi :)

Wow I never knew that lol :)

Thanks very much as its rare I learn something new about 928s ...

All the best Brett :)