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Discussion Starter #1
I am in need of some help I was driving back on the freeway yesterday and I was going around 70 and something caught my eye on the panel it was the speed gage. It had dropped to 0 then back up again to 70 the speed limit that I was going. Then back to 40 then back to 70 again. I never hit the brakes or let off the gas what so ever. Anyone else have this problem? What is the problem? Suggestions?
 

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this could be multiple causes like different wheels or any wire tapping into any of the vss or related module wiring.
However if none of that is done... basically the signal is being lost. If this is the only gauge that fluctuates you can count on it being in the vss (vehicle speed sensor ) circuit and not so much in the i/c (instrument cluster) circuit. Do you have a check engine light? Nine times out of ten this is due to the vss plastic gear breaking.However you should set a code and this code is one that wil activate a cel. See if it keeps happening. A vss light or abs light should be coming on soon and this will verify the concern
 

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Discussion Starter #3
this could be multiple causes like different wheels or any wire tapping into any of the vss or related module wiring.
However if none of that is done... basically the signal is being lost. If this is the only gauge that fluctuates you can count on it being in the vss (vehicle speed sensor ) circuit and not so much in the i/c (instrument cluster) circuit. Do you have a check engine light? Nine times out of ten this is due to the vss plastic gear breaking.However you should set a code and this code is one that wil activate a cel. See if it keeps happening. A vss light or abs light should be coming on soon and this will verify the concern
There is no check engine light and I havent done any mods to my Charger at all. Would this be something to take into the dealer? What do you mean by.."However you should set a code and this code is one that wil activate a cel."
 

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if you lose a speed signal due to a vss or abs wheel speed going poop it will set the check engine light or abs light based on which system the problem is in. The vss takes speed signal from tranny and will set a check engine light, the wheel speeds get signal from the wheels and send to the abs module which will set the abs light. See if you can get a light to come on first. Otherwise the dealer will have to drive the car til the light sets as that is where they get their info. That would be a waste of your gas and if its under warranty its likely the tech wont spend much time on trying to get it to act up cause if he does and it doesnt screw up he lost all that time and wont get paid.
I'm off to work, i will check this thread tonight around midnight and see if you've updated anything. peace
 

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Discussion Starter #5
if you lose a speed signal due to a vss or abs wheel speed going poop it will set the check engine light or abs light based on which system the problem is in. The vss takes speed signal from tranny and will set a check engine light, the wheel speeds get signal from the wheels and send to the abs module which will set the abs light. See if you can get a light to come on first. Otherwise the dealer will have to drive the car til the light sets as that is where they get their info. That would be a waste of your gas and if its under warranty its likely the tech wont spend much time on trying to get it to act up cause if he does and it doesnt screw up he lost all that time and wont get paid.
I'm off to work, i will check this thread tonight around midnight and see if you've updated anything. peace
The check engine light will come on automaticly if there is a problem. It just doesnt seem right that this happened and no light came on?
 

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Mine has done it a couple of times. 1st time driving to Miami and then again last week coming back from Spring Hill. Did yours happen with the cruise on? That is when mine happened. No light has lit. It did seem like the engine cut-off for a second that caused me to look down. But it was extremely fast. Like you the speed limit gage went from 80 to 30 then back up immediately.

Hope this does not cause a breakdown while on the road.

Hopefully someone will report what the fix is.

Take care,
 

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the check engine light will not come on "automatically". Trust me on that. For the cel to set it has to see the same "bad" condition for two drive cycles. A drive cycle is not a trip to the gas station. A drive cycle is a serious of events determined by the pcm. I.e. 40-0 stop 0-60 accel, 20-50 accel. Whatever. These parameters change based on car. If it does not see it two cycles in a row it WILL NOT set the light. I can dig up the drive cycle info out of the service manual if you need so you can see the parameters that have to be met if this will help you
 
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