156 ECU pinout SPEEDO pinout

[ccaltabiano86]

My speedo is out by about 4% on my 2001 156.
Have been trying to find a wiring diagram for the ECU and speedo as I have made a JAYCAR speedo kit but dont want to pull out dash to get to speedo wire (would rather do it at ECU end, and then hide the box with the ECU)

Does anyone know what pin the speedo output is on? am I correct to asume it is on the ECU?
Would it be easier to just go to an auto electrician?

Thanks,
Chris

[colcol]

When you say the speedo is 4% out, do you mean 4% at 40 klms and 4% at 100 klms, or say a constant say 4 klms slow or fast, if it is a constant figure, you can remove and reposition your speedo needle, how do you know its out?, have you been comparing to your GPS, have a look at your tyres as well, as fully worn down tyres will make the speedo read different, than brand new ones, trouble is now, your speedos out 4% and the speeding fines tolerance is say 3%, you are in trouble, the speedo in my 156 is spot on comparing it to my GPS, and looking at those 'check speed here^' signs they have on freeways in Melbourne, trouble is, they are never working, Colin.

[ccaltabiano86]

hey Colin,
It's about 4% out, so when im traveling 62 it shows 60 on dash, 84 / 80, 104 / 100... and so on.
I upgraded my wheels to 19", hence the reason its out. prior to replacing I checked speedo to gps and it was spot on, now it is out.
I have been cautious to drive 5km under limit, but it is getting annoying.

If I cant find the wire at the ECU I guess I will have to pull out dash and get to the back of the speedo... But does anyone know what wire is the speed input on the wiring harness?

Thanks,
Chris

[colcol]

Look up '147 speedo calibration' on this forum in the 147-156 section, almost the same as what we are talking about now, Colin.

[Cool Jesus]

Not up to speed with differing models of 156s, however I found this with a quick search. The third diagram indicates km/h as E10 with the ECU pinout being 36, or connecter D5 with a pinout of B12 (I think?).

Found it here
http://homepage.mac.com/paul_denyer/selespeed/index.html

[ccaltabiano86]

My search function was not working... Or maybe I was been too specific in my search criteria.
Will look into it. Thanks Colin, and thanks cool Jesus for diagrams