Speedometer failed but ODO and day-counters still work

My trusty old Mitsubitsu Space Star from 2000 or abouts recently ran out of juice because I left the lights on, and after jump-starting it this cold dark morning and driving it a bit to let the computer get re-acquainted with the engine, I noticed my speed indicator stuck at 0.

The car was itself running fine and the day-counter and ODO meter added up the kilometers, which was puzzling. Are they not running off the same sensor?

A quick round of Google showed me what must have happened; [1] , [2]  when jump-starting a car, or re-connecting it’s battery, voltage mulst have spiked which sometimes causes the Speedometer needle to go full 360..

Sample speedometer with needle in normal resting position

And indeed, on closer inspection I could see it was stuck on the other side of the little pin, unable to move any further.

Sample speedometer with needle on the wrong side of the ‘pin’.

Ready for an afternoon of taking things apart, I was pleasantly surprised at how simple the solution to this issue can be:

  1. For some cars, probably a bit more advanced than my humble Space Start, one can push down the reset button of the day-counter whilst, after or before inserting and turning the key for up to a full minute. I tried it all, to no avail.
  2. Mention was made of the display needing to be in ODO-mode for this to work but this does not apply to my car; switching between the A and B counters and repeating the above did not help either.
  3. In the end, what did reset the Space Star Speedometer was the simplest option on offer; disconnecting the battery (the “-” terminal) for a full five minutes, and then simply re-connecting the system.

After disconnecting the battery I could see the needle had moved back somewhat already and reconnecting it five minutes later, the needle jumped back to 0 and, on a test-drive, indicated as before.

That’s it. No disassembly, no visit to the garage, done in 5 minutes.