speedo/odo/DIC problem
Thread Starter
2nd Gear
Joined: Mar 2017
Posts: 2
Likes: 0
From: California
speedo/odo/DIC problem
I have a '97 Corvette with about 93000 miles on it.
A couple of months ago I noticed the speedometer getting kind of erratic and it became worse and worse over the next few days, bouncing from 0 mps to thre right speed then back to 0 mph. Then it quit working completely, showing 0 mph. It looked like a wire or connection may have started working loose and finally broke completely, or shorted out.
At the same time the odometer also quit, and the DIC went whacky, displaying each of the gauge reading over and over, and it quit responding to any button selections.
I guess speed sensor is ok because I can set the cruise control and it momentarily gives an accurate speed on the DIC compared against my GPS, and the cruise holds the speed fine. The engine runs fine and tranny shifts correctly too.
Any ideas what may have happened and how to fix it?
Thanks!
A couple of months ago I noticed the speedometer getting kind of erratic and it became worse and worse over the next few days, bouncing from 0 mps to thre right speed then back to 0 mph. Then it quit working completely, showing 0 mph. It looked like a wire or connection may have started working loose and finally broke completely, or shorted out.
At the same time the odometer also quit, and the DIC went whacky, displaying each of the gauge reading over and over, and it quit responding to any button selections.
I guess speed sensor is ok because I can set the cruise control and it momentarily gives an accurate speed on the DIC compared against my GPS, and the cruise holds the speed fine. The engine runs fine and tranny shifts correctly too.
Any ideas what may have happened and how to fix it?
Thanks!
Tech Contributor
Joined: Oct 1999
Posts: 41,030
Likes: 9,783
From: Charlotte, NC (formerly Endicott, NY)
Well I was thinking the Stepper Motor for the Speedo may have failed but then you say the DIC is acting weird as well. The first thing to do is to check for codes using the C5's On Board Diagnostics. You can initiate them from the switches to the right of the IP.
You could have some wiring problem between the PCM and the IP so check the wires going from the PCM to the IP. The problem with the DIC may indicate you have a fatal error requiring replacement of the IP which wouldn't be cheap.
I am attaching a diagnostic from the FSM to help you. Use the C5 built in diagnostics in place of the scan tool mentioned in the diagnostic.
One other thing you should do is check all the voltages and grounds going to the IP and to the PCM. This failure could be due to a low voltage level across the module and corrosion, dirt may have increased connector resistance so the voltage drop across the module is reduced too much.
Bill
You could have some wiring problem between the PCM and the IP so check the wires going from the PCM to the IP. The problem with the DIC may indicate you have a fatal error requiring replacement of the IP which wouldn't be cheap.
I am attaching a diagnostic from the FSM to help you. Use the C5 built in diagnostics in place of the scan tool mentioned in the diagnostic.
One other thing you should do is check all the voltages and grounds going to the IP and to the PCM. This failure could be due to a low voltage level across the module and corrosion, dirt may have increased connector resistance so the voltage drop across the module is reduced too much.
Bill
Last edited by Bill Dearborn; Mar 22, 2017 at 09:19 PM.
Thread Starter
2nd Gear
Joined: Mar 2017
Posts: 2
Likes: 0
From: California
Thanks for the advice and the diagnostic, I'll check out the wiring. Not sure if I can do a diagnostic run because it doesn't seem to take any input from the right side buttons at all now no matter what sequence I try.
Also, I forgot to mention that when I turn on the ignition, both the speedo and tack do their full swing test ok, so the motor is apparently ok.
Also, I forgot to mention that when I turn on the ignition, both the speedo and tack do their full swing test ok, so the motor is apparently ok.
