96 Corvette Speedometer Issue
Thread Starter
7th Gear
Joined: May 2011
Posts: 7
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96 Corvette Speedometer Issue
I have a 1996 Corvette LT4 and have ongoing issues with the speedometer. The speedometer has stopped working so the LCD just displays "0" no matter what speed I am going. Also, the LCD will not display anything unless I turn on the parking lights or head lights. I have had the CCM checked and replaced the vehicle speed sensor. The odometer is working, so I'm not sure what the problem is. Anyone have any new ideas I can check? Thanks
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
this?
You say the odometer is working. So the odometer does increment as you drive the vehicle? If yes that would confirm the VSS is working.
When the park or headlight switch is turned on does all information display properly like fuel gauge and
the only problem is the speedometer displays 0 even
when the vehicle is moving?
How was the CCM checked?
If you short pin 4 to pin 12 on the diagnostic connector above the drivers right knee and turn the ignition On. DTC's for the CCM should be displayed on the LCD. Module 1 is for the CCM. Turn the headlight switch on so you can see the LCD display.
Last edited by Hooked on Vettes; Feb 25, 2013 at 03:32 PM.
Thread Starter
7th Gear
Joined: May 2011
Posts: 7
Likes: 0
Yes the orange screen LCD displays all the other information when the parking lights or head lights are on. Only the speedometer reads "0". The odometer is working properly. I pulled the CCM and sent it in to a company to be tested. It was found to be performing properly.
Thread Starter
7th Gear
Joined: May 2011
Posts: 7
Likes: 0
This is a new problem. The speedometer was working fine and all of a sudden stopped. The LCD screen is the dull brown with nothing showing when the lights are off, but when you turn on the lights, the orange background lights up and all of the usual information is displayed. Only the odometer reads zero.
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
Everything points to the CCM.
You should verify no codes are set for the CCM.
Here's some other tests you should try.
The dark LCD display could be the result of a ambient light sensor circuit problem which is monitored by the CCM to control the back lighting brightness.
With the ignition on and park/headlights off, shine a flash light on the sensor. The LCD back lighting should increase. If no change that would point to the CCM.
Normal operation with ignition on and headlights on if you place your finger over the ambient light sensor the display should dim.
If the cruise control works and the speedometer doesn't, that would also point to the CCM.
Can you post the name of the company that said the CCM tested good?
.
You should verify no codes are set for the CCM.
Here's some other tests you should try.
The dark LCD display could be the result of a ambient light sensor circuit problem which is monitored by the CCM to control the back lighting brightness.
With the ignition on and park/headlights off, shine a flash light on the sensor. The LCD back lighting should increase. If no change that would point to the CCM.
Normal operation with ignition on and headlights on if you place your finger over the ambient light sensor the display should dim.
If the cruise control works and the speedometer doesn't, that would also point to the CCM.
Can you post the name of the company that said the CCM tested good?
.
Last edited by Hooked on Vettes; Feb 27, 2013 at 11:40 AM.
