Speedometer fluctuating?

Tiny
JAZZYWANTSTOKNOW
  • MEMBER
  • 2011 HYUNDAI SANTA FE
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
When I turn my car on, or while idling, my speedometer will jump all over the place. Sometimes it only goes back and forth between 0-20, other times it goes all the way to 140 at the speedometer max. While driving, it behaves normally, despite being off by 5 MPH
Since it started, both my battery and Alternator have been replaced.
Thursday, January 19th, 2023 AT 1:40 PM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

Based on your description, I suspect there is a voltage spike to the speedometer head in the vehicle that may be coming from the printed circuit board in the cluster. However, there is only one way to test. I have directions for testing the speedo and the vehicle speed sensor. I have attached both below.

The test for the speedometer is something you will not likely be able to perform at home. Take a look at it. On the other hand, we can test the VSS to see if there are any odd signals or voltage changes when the vehicle isn't moving.

Take a look through the directions and let me know if you feel comfortable performing them.

Let me know.

Joe

See pics below.
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Thursday, January 19th, 2023 AT 6:03 PM

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