Erratic speedometer

HYELINE

MEMBER
1993 CHEVROLET LUMINA
3.1L
6 CYL
2WD
AUTOMATIC
150,000 MILES

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?

Monday, February 8th, 2021 AT 10:16 AM

5 Replies

KASEKENNY

MECHANIC
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

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Tuesday, February 9th, 2021 AT 4:44 PM

HYELINE

MEMBER
10 POSTS

Thank you.

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Wednesday, February 10th, 2021 AT 12:44 PM

KASEKENNY

MECHANIC
18,907 POSTS

You are welcome. Let us know how this turns out as I am curious about this one. Thanks

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Wednesday, February 10th, 2021 AT 6:57 PM

HYELINE

MEMBER
10 POSTS

So I pulled the connector out, cleaned it up good. Seemed to do the trick!

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Monday, February 15th, 2021 AT 9:19 PM

KASEKENNY

MECHANIC
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.