Speedometer inop intermittant - 2000 Chevrolet 2500

Check out this post telling the reasons the speedo is inop.

https://repairpal.com/mitsubishi/diamante/speedometer-not-working

Speedometer and/or Odometer Inaccurate or Inoperative
Test Description
The number below refers to the step number on the diagnostic table.

1. This test procedure may cause DTCs to set, which may cause other systems to be inoperative or disabled.

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics
1

Did you perform the Diagnostic System Check - Vehicle?
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

1. Install a scan tool.
2. Raise the vehicles drive wheels. Refer to Lifting and Jacking the Vehicle in General Information.
3. Start the engine.
4. Place the transmission into drive.
5. With the scan tool, observe the Vehicle Speed Sensor (VSS) parameter in the engine control module (ECM)/powertrain control module (PCM) Engine Data 1 data list.

Does the VSS parameter match the speedometer display?
Go to Step 3
Go to Step 4

3

Does the odometer operate properly?
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
Go to Step 4

4

Replace the instrument panel cluster (IPC). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?
Go to Step 5
--

5

1. Operate the system in order to verify the repair.
2. Use the scan tool in order to clear the DTCs that may have set in other modules during diagnosis.

Did you correct the condition?
System OK
Go to Step 2

For speedometer problem click the link below :---

How to trouble shoot speedometer?
http://schematicsdiagram.blogspot.com/2011/06/speedometer-not-working.html
-----------speedometer not working? http://technoanswers.blogspot.com/2012/01/1996-fiat-bravo-speedometer-not-working.html
---------Speedometer runs backward?

http://technoanswers.blogspot.com/2012/01/speedometer-runs-backward.html

----------
Warning lights on and speedometer died? http://howtobyme.blogspot.com/2011/08/warning-lights-on-and-speedometer-died.html
---------ABS & Brake lights warning indicator steady on dash and speedometer not working? http://howtobyme.blogspot.com/2011/11/abs-brake-lights-warning-indicator.html
--------Odometer works properly but speedometer works intermittently? http://technoanswers.blogspot.com/2012/01/odometer-works-properly-but-speedometer.html
----------speedometer is jumping? http://schematicsdiagram.blogspot.com/2012/01/isuzu-rodeo-speedometer-is-jumping.html
-----------This will help.Thanks.

not a good idea to do a voltage test on a computer component, it can result in damage to the ECM.
if only the speedometer is not working and the other gauges do work, the first place to start is the speed sensor, it is the most common issues with inoperative speedometers.

neoprene gear in transmission were the speedometer cable goes into transmission should not have a dished appearance if you pulll it out of transmission look at it from the side it should appear flat from the start of the gear to end of gear no dish down in center

Usually it's the opposite. The speedometer works and the odomater and trip meter go inop. Most likely the speedometer assembly is bad. If the odometer is working you have a signal from the gray and black wire .

Hello! It sounds as if you have a wheel speed sensor that is failing. The wheel speed sensor calculates the wheel/tire revolutions and sends this information to the speedometer, which then displays that information as MPH/KPH. On 97-06 Grand Prix's this and the ABS sensor are the same module, and in order to replace, you must replace the entire hub assembly. Here is a view of the hub assembly from the back side of the hub/wheel assembly. You may want to inspect the sensor wires for any fraying, loose connections, etc.



Hope this helps. Thanks for using FixYa!

Yes your speedometer, and odometer are controlled by your speed sensor.

You should have a speedometer cable that runs from the back of the trani, thru the fire-wall, and into the back oh the gauge cluster.

It may be a faulty speedometer with a short inside, or a short on speedometer wirings or connector.

Whenever car vibration cause the wiring to short, there you lose speedometer and trans functionality.

You need to access the speedometer connector and wirings to
instrument panel to fix this.