04 Impala Speedometer gone haywire.

[mark ix]

Hi guys, I am having a real time with this one . I have a 04 Impala LS with 43k miles on it and all of a sudden the speedometer started reading about 50 mph faster that I was moving. At stop signs it still reads about 60 mph and sometimes when I'm driving along it goes all the way to 120mph and beyond . Also there is a strong odor of melting plastic when we park the car and shut it off. The rest of the cluster works fine.
I have located the speedo sensor on the tranny and the wires look to be ok and are connected. I can't seem to find any melted wires or anything. The CEL has not come on at all. The tranny shifts fine and odometer is working fine. Are there any fuses that I can check (it's never that easy!!!!) Any ideas?

Thanx, Mark

[Blue Bowtie]

Welcome Aboard!

The signal to the speedometer comes directly from the PCM, and not the VSS (Vehicle Speed Sensor). I've recently had two of these fail on me on different GM models, so it's fresh in my mind. The PCM speedometer output relies on the VSS for correct input, but that same input is used as a reference to control the transmission shift points. If the transmission is apparently operating normally, and the "Check Engine" warning light is not on, I'd suspect either the signal from the PCM or the speedometer (instrument) itself. A competent shop should be able to monitor the signal with an oscilloscope and determine which it might be.

[mark ix]

Thanx, for the info Blue. I have a couple of questions: Did you notice any odors, like melting plastic when you had the two failures? I noticed this odor when looking under the hood, only when the speedometer is not working properly. When it functions fine there is no odor. And what does PCM mean?

Thanx, Mark

[BNaylor]

PCM means Powertrain Control Module. It is located in the air box assembly. Where is exactly is the smell centered in the engine compartment? There is a company called Southern Electronics that will repair GM IPs.

[mark ix]

When the odor occurs it seems to be more near the driver side of the engine, around the radiator hoses and battery area.

Mark

[MsDixiesImpala]

I have a 2004 Chevy Impala. I'm having problems with the speedometer. At first I thought that it had something to do with the weather. The car was manufatured in Canada and spent it's first years in Georgia before coming here to Mississippi. Some mornings when I take my children to school, it will say that I'm going 0 miles per hour. Then some mornings it will show something faster. I thought by turning the car off it would reset itself, that didn't work. I took it to the dealership that I bought it from and was told that it was the INSTURMENT CLUSTER PANEL. And that there have been several people coming in with this same problem with different years but the same make and model, Chevy Imapala. I have been trying to find a recall on this. Can someone, anyone, help me??? I would think that if there have been several people that have had the same problem, that there would be a recall on this???? PLEASE HELP ME! THANKS.
I HAVEN'T SMELLED ANY ODORS. I NOTICE THAT SOME SAID SOMETHING ABOUT AN ODOR. I HAVEN'T HAD ANY.

[MsDixiesImpala]

What year model do you have? Mine is a 2004 Chevy Impala. I haven't had an odor smell. Just that the speedometer is being really screwy. No lights coming on, such as the check engine.

[blackimpalals]

Just picked up an LS with 24K miles. Driving home from the dealer the speedo goes crazy. Guess I'll be finding more about this too. Every other gauge is ok.
From what I understand it's a communication problem between the IPC (instrument panel cluster) and the PCM (powertrain control module). I'm getting it checked soon. My guess is I'll need a new cluster. I'm sure that'll be 2-$300 as usual.

[adamace1]

When this is happening is it efecting the miles on the car too? Like if you didn't fix it would it say you had way more miles on your car than it does, or is it just a speedo problem?

[blackimpalals]

In my case it's strictly a speedo issue. Under warranty I'm having the instrument cluster replaced. If a whole bunch of instruments are messed up then the powertrain control module may be suspect, particulary if the transmission is shifting goofy.

[seve5020]

I am having the same exact problem of the "floating needle" on my speedometer but it is not only my speedometer. My fuel gauge needle and RPM needle does the same thing and sometimes they all go back to normal for a little while but eventually my needles are floating somewhere on my speedometer. I called and got an estimate of spending about $400 to fix this because they have to send it out to get a new one and then they have to program the new one to the mileage of my car. I am not too happy with this. Does anyone have another option for this or has anyone heard of a recall on this malfuction? Please respond.

[j cAT]

Originally Posted by seve5020

I am having the same exact problem of the "floating needle" on my speedometer but it is not only my speedometer. My fuel gauge needle and RPM needle does the same thing and sometimes they all go back to normal for a little while but eventually my needles are floating somewhere on my speedometer. I called and got an estimate of spending about $400 to fix this because they have to send it out to get a new one and then they have to program the new one to the mileage of my car. I am not too happy with this. Does anyone have another option for this or has anyone heard of a recall on this malfuction? Please respond.

go on line to n.h.t.s.a. enter your model year and other info and see if it is listed if not , there are contact numbers and forms to describe your failure ....this i believe should be recall saftey issue......

[TEXAS_IMP_RIDA]

HEY GUYS I'M HAVING THE SAME PROBLEM AND SOMEONE HOOKED ME UP WITH THE SOLUTION TO THE PROBLEM... CHECKOUT THIS WEBSITE http://home.comcast.net/~bbengineer/cars/impala/ OR EMAIL PERRY @[[email protected]], HE WILL BE ABLE TO EXPLAIN WHAT THE PROBLEM IS AND GIVE YOU SOME ADVICE. HE SERVICES AND SALES GUAGE CLUSTERS FOR IMPALAS AND MONTE CARLOS... I ORDERED MINE LAST WEEK AND SHOULD BE RECEIVING IT TODAY.... PLEASE CHECK HIM OUT, HE'S ALOT QUICKER AND CHEAPER THAN WHAT WOULD HAPPEN IF YOU WENT TO A SHOP...

[Admiral Michael]

Originally Posted by TEXAS_IMP_RIDA

HEY GUYS I'M HAVING THE SAME PROBLEM AND SOMEONE HOOKED ME UP WITH THE SOLUTION TO THE PROBLEM... CHECKOUT THIS WEBSITE http://home.comcast.net/~bbengineer/cars/impala/ OR EMAIL PERRY @[[email protected]], HE WILL BE ABLE TO EXPLAIN WHAT THE PROBLEM IS AND GIVE YOU SOME ADVICE. HE SERVICES AND SALES GUAGE CLUSTERS FOR IMPALAS AND MONTE CARLOS... I ORDERED MINE LAST WEEK AND SHOULD BE RECEIVING IT TODAY.... PLEASE CHECK HIM OUT, HE'S ALOT QUICKER AND CHEAPER THAN WHAT WOULD HAPPEN IF YOU WENT TO A SHOP...

I agree, he is awesome. He answered alot of questions about putting a overhead DIC in an Impala (I haven't done it yet tho).

[TEXAS_IMP_RIDA]

I I Recieved My Cluster Last Night Guys... If I Can I'll Post A Pic Of How It Looks...