Erratic speedometer

1993 CHEVROLET LUMINA
150,000 MILES • 3.1L • 6 CYL • 2WD • AUTOMATIC
Avatar
HYELINE
  • MEMBER
  • 10 POSTS
Hello, the speedometer acts erratic when driving. It will function fine and suddenly go to 100 then drop and appear normal. So far, I’ve changed the vehicle speed sensor and that didn’t help. What else could it be?
Feb 8, 2021 at 10:16 AM
Advertisement
Avatar
KASEKENNY
  • CERTIFIED EXPERT
  • 18,907 POSTS
More then likely the cluster has failed. The PCM is supposed to act like the buffer and take the voltage from the speed sensor and then send it to the other components that need it like the speedometer. However, it could be the PCM itself as well.

Do you have a scan tool that can monitor the vehicle speed? If you do and the scan tool is acting the same as the speedometer then you know the PCM or VSS is the issue because the speedometer is just displaying what it is told.

However, this is unlikely but below you will find all the info for this.

Let's run through this and we can go from there. Thanks
Images (Click to enlarge)
Attached Media
Attached Media
Attached Media
Attached Media
Attached Media
Attached Media
Feb 9, 2021 at 4:44 PM
Avatar
HYELINE
  • MEMBER
  • 10 POSTS
Thank you.
Feb 10, 2021 at 12:44 PM
Advertisement
Avatar
KASEKENNY
  • CERTIFIED EXPERT
  • 18,907 POSTS
You are welcome. Let us know how this turns out as I am curious about this one. Thanks
Feb 10, 2021 at 6:57 PM
Avatar
HYELINE
  • MEMBER
  • 10 POSTS
So I pulled the connector out, cleaned it up good. Seemed to do the trick!
Feb 15, 2021 at 9:19 PM
Avatar
KASEKENNY
  • CERTIFIED EXPERT
  • 18,907 POSTS
That is awesome. Great information and I am sure that will help others. Thanks for following up with us and sharing that fix.

Please come back to 2CarPros next time.
Feb 16, 2021 at 5:25 PM