Speedometer jumping up and down

2009 CHEVROLET IMPALA
114,000 MILES • 5.3L • V8 • 2WD • AUTOMATIC
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LLG504
  • MEMBER
  • 1 POST
I have the car listed above SS model. My speedometer has been jumping from 0 to 40 up and down. There is no engine light on. I changed my speed sensor on passenger side. Should I change both input and output sensor or is there something else I am missing?
Jun 10, 2018 at 12:45 PM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Good morning.

The vehicle speed sensor is the one that controls the speedometer. The input and output sensors only effect shifting.

Did you check the connector at the sensor for any loose or damaged wires?

This could be the cluster that is the issue. The way to confirm is to use a scan tool, not a code reader to see if the signal from the sensor is the same as the reading on the dash.

If the reading is the same, it could be a wiring issue. If the reading is steady, it could be the cluster itself malfunctioning.

Roy
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Jun 10, 2018 at 8:10 PM
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