2002 Corvette M6 - Speedometer Troubles
Thread Starter
Safety Car
Joined: Jan 2019
Posts: 4,308
Likes: 3,455
From: Somewhere, Florida
St. Jude Donor '20-'21-'22-'23-'24
2002 Corvette M6 - Speedometer Troubles
I did a search on this forum and in the General forum for "speedometer" and didn't really come up with any kind of answers. Also cross-posted to the C5 Corvette 1997-04 Facebook group, but here it is:
2002 Corvette with manual trans:
My speedometer is erratic. Sometimes it works, sometimes it doesn't. The speedo seems to work perfectly fine at highway speeds, but the car doesn't know when it's slowing down (it will say 0mph when I'm clearly still moving/in gear). I tried cleaning the grounds behind the headlights, and though they were slightly corroded, it didn't make any difference.
So I looked up the transmission speed sensor, but every listing on RockAuto says 4L60E. Is it the same part for the manual? Anyone ever changed it or know where it's located? Would definitely like to have a functioning speedometer.
2002 Corvette with manual trans:
My speedometer is erratic. Sometimes it works, sometimes it doesn't. The speedo seems to work perfectly fine at highway speeds, but the car doesn't know when it's slowing down (it will say 0mph when I'm clearly still moving/in gear). I tried cleaning the grounds behind the headlights, and though they were slightly corroded, it didn't make any difference.
So I looked up the transmission speed sensor, but every listing on RockAuto says 4L60E. Is it the same part for the manual? Anyone ever changed it or know where it's located? Would definitely like to have a functioning speedometer.
Thread Starter
Safety Car
Joined: Jan 2019
Posts: 4,308
Likes: 3,455
From: Somewhere, Florida
St. Jude Donor '20-'21-'22-'23-'24
I work at a dealer and did some research last night.
Rock Auto lists part number 12369458 as the correct one, but it specifies Automatic trans only.
GM disagrees, and says it's the same for both, so I ordered one from work. It'll be here tomorrow - so here's hoping to a functional speedometer!
Rock Auto lists part number 12369458 as the correct one, but it specifies Automatic trans only.
GM disagrees, and says it's the same for both, so I ordered one from work. It'll be here tomorrow - so here's hoping to a functional speedometer!
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
100% on the money... Look for cable and or connector damage.. That circuit is NOT grounded! It has a reff voltage and a signal output. Both wires go to the PCM. The PCM feeds the speedo value to the IPC through the serial data line.
Thread Starter
Safety Car
Joined: Jan 2019
Posts: 4,308
Likes: 3,455
From: Somewhere, Florida
St. Jude Donor '20-'21-'22-'23-'24
That explains why the grounds did nothing for me (though, I did still find some corrosion so not a completely useless endeavor).
The car went to my trusted shop that did the PCM tuning on my other project today for a harmonic balancer replacement and new speed sensor. I'm sure he will find the broken wire, if applicable.
At 262,000 miles, I wouldn't be surprised if the sensor has failed. I'll have to make an introduction post soon.
The car went to my trusted shop that did the PCM tuning on my other project today for a harmonic balancer replacement and new speed sensor. I'm sure he will find the broken wire, if applicable.
At 262,000 miles, I wouldn't be surprised if the sensor has failed. I'll have to make an introduction post soon.
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