2003 Chevy Suburban speedometer

2003 CHEVROLET SUBURBAN
148,552 MILES • V8 • 2WD • AUTOMATIC
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JUDDRAY
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Speedometer reads 80mph when going 25mph. Changed speed sensor 2 times from O'reillys. Went to GM and purchased and got same result. Each time a new speed sensor was installed (3 altogether) the speedometer started working perfect and after aprox 2 weeks starts eradict speeds. Surburban is now stuck at 50mph sitting in driveway. If I change the sensor it will automatic go to zero and work perfect.
Is it the part going bad or is something else causing my speedometer problem?
Thks in advance, Ray
May 3, 2010 at 1:48 PM
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2CARPRO JACK
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For something like this, it will need to go on a scanner to see if the computer is receiving a correct speed signal from the sensor.If the trans shifts correctly during all of this, the PCM is most likely getting a good signal and theproblem is in the instrument cluster or the signal between the PCM and the cluster
May 4, 2010 at 8:17 AM
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JUDDRAY
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[quote:7d82b421e4="2CarPros Jack"]For something like this, it will need to go on a scanner to see if the computer is receiving a correct speed signal from the sensor.If the trans shifts correctly during all of this, the PCM is most likely getting a good signal and theproblem is in the instrument cluster or the signal between the PCM and the cluster[/quote:7d82b421e4]


I just don't understand when a new sensor is installed
it works perfect for approx 2 weeks.
May 4, 2010 at 1:30 PM
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2CARPRO JACK
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Thats why we need to know what the signal is to the PCM when it is not reading correctly.Odds are good if you reinstalled the sensor that you replaced, it would be ok for a few weeks as well.
May 5, 2010 at 7:52 AM
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CH3VYCR4ZY
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These models had issues with the Instrument Cluster diodes. My 03 had same prob. I replaced the cluster (which is super easy to do) and all gauges returned back to normal. You can go to local parts dealer and you have to fill out a form (to verify mileage) along with your old cluster. Dorman was the parts manufacturer I used, I don't know if there is any others.
Apr 15, 2011 at 10:18 PM