What Would Cause My Speedometer To Just Stop Working

Posted in Performance Chips

I have a 2004 Monte Carlo and this evening just out of the blue when I parked it to pick up pizza I noticed that the speedometer was stuck at 70 mph. The car was turned off and was reading that speed. It had been reading correctly beforehand. I cranked it back up and it continued to read 70 mph. On the way home it kept going higher and higher until it maxed out at 120 plus (it couldn’t go any higher). Is this a common thing that happens? We just had a bad cold spell where the temps got down to the teens (if that makes any difference). I had been driving for about an hour before this happened so the car was plenty warm. Any suggestions would be greatly appreciated. Thanks

There are 5 Answers for "What Would Cause My Speedometer To Just Stop Working"

    1. david z says:

      unfortunately it has to go to GM for its warranty replacement… sorry i haven’t got better news for you… shoulda bought a ford.

    2. wi_saint says:

      You need a new cable or a new speedo bullit.

    3. Ron / Yogi says:

      As David says, return it to GM if they will cover it under warranty.
      If not you might get by with just greasing the speedo cable, worse case replacing the cable. It is not an expensive item nor does it take long to replace. Most any shop / even body shop can replace.

    4. dodge man says:

      i own a repair shop,and its under warranty ,,but id say either the speedometer its self went bad ,,or the speed sensor went out on it, i have see this happen before,,it was the main unit in the dash that did it,,but id be calling the dealer on this one,,use that warranty while you can to get all the bugs worked out of it,,good luck i hope this help,s,,have a good x-mas.

    5. stallion1948_lloyd says:

      theres a little plastic gear in the tranny,that operates the speedometer.maybe the gears are stripped off the gear.or maybe the core broke.