I have a metric KPH instrument cluster in my 1997 850R. This is a daily driver so I switched out the instrument cluster with a speedo reading MPH. I picked up an extra cluster and broke down both clusters to swap the instruments panel alone (including all potentiometers (pots)). Both speedo pots had the same model number on them with a date stamp of late 95 for the replacement. I believe I read something regarding early 1990s cluster may not work correctly in a 1997.

My thought was the original metric board would tell the same pots what to read, with the KPH under the MPH on the speedo dial and all is good…

On the first test drive the speedo accumulated positively. Below 40mph, the accuracy is close, but accumulating. Above 40mph, +10MPH over 50MPH. Have yet to drive the car above 65mph for data collection. The kph was just as inaccurate.

I swapped the original metric pot with the transplanted pot and received the same result. Lightly sanded and cleaned the contacts, same results. Reset the hand and received the same result. Unplugged the battery to attempt to reset the CPU. Same result.

Found a technical document for a 1992 850 talking briefly about the 48 plus of a speed sensors and resetting the regional setting when replacing the cluster, with nothing more.

Not sure if the speedo was accuracy in the first place, as I’m am metrically challenged.

Does anyone know if the is some way to calibrate the replaced speedo? Or should I be barking up the wheel speed sensors tree?

Thanks for the read.

 

From what I remember some of those 850 instrument clusters were programmable for the different tire sizes used on various models - (e.g. short tires were installed on the R cars)

Tire size was programmed using a VST -

Volvo System Tester VST 9988686

Doubt you would find one easily (although I just sold mine a few months ago to a Guy in Atlanta)

 

Just got the 850 OBD app up and running! Found the wheel size set to standard and changed it to a custom circumference. It appears speeds up to 70mph (+/-2) agrees with the GPS!! I did notice the original metric cluster removed from the car had been professionally repaired. Never ready confirmed the speedo was correct before starting this process. Any ideas how this setting could be lost?

Switching to KPH.
While running live data in the 850 OBD app, I noticed the displayed (ECU?) speed 5 to 10 kph faster than GPS and speedo displayed speed. And noticed the tach showing an ideal speed of 910 rpm when the ECU showed 832 rpm (which is where it usually sits). Stomping on the throttle, the RPMs go up to 9000rpm!! ECU shows something around 5000 rpm. Have not found the tach settings are yet. I might have causes the tach issue tinkering with this app.

Any thoughts would be appreciated.