Speedometer fluctuating?

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

JACOBANDNICKOLAS

MECHANIC
110,176 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.

Images (Click to make bigger)