GMC Sierra: VSS – Circuit Malfunction

P0500 OBDII Trouble Code that can affect the GMC Sierra‘s Vehicle Speed Sensor (VSS). The VSS sends a signal to the engine’s computer letting it know how fast that the vehicle is going.

This signal is used by the Sierra for many functions. This signal controls transmission shifts and ABS. It also regulates cruise control and the speedometer. Repairing this should be a top priority.

GMC Sierra P0500 Symptoms

There will be variations depending on your model year or other conditions. These are some of the most frequent symptoms for P0500.

• Tempoometer failure– Without a properly working vehicles speed sensor, the speedometer will not register any speed. It’ll just sit at 0 MPH while you are driving. You can see the Odometer Could not function at all
• Cruise Control Failed– When a vehicle is not getting a signal from the VSS, it’ll not let the cruise control engage. This makes sense since it can’t control the speed when it doesn’t know how fast it is going.
• Harsh Shifts It is possible for the transmission to shift in a different way than usual.
• Anti-Lock Brakes– The Sierra’s ABS may not work or could be compromised. VSS is one part of a more complex set of sensors which prevents the wheels locking under high break pressure.

GMC Sierra - P0500: Causes

• Bad VSS– More often than not, when P0500 is thrown, replacing the Vehicle Speed Sensor will remedy the problem. These are It's also quite affordable.
• Trouble with the wiring– Due to the location of the VSS, the wiring harness going from the vehicles computer to it can often become damaged and open/short out. If this happens, Sierra won't be able determine the VSS readings. It would be great to take a good look at your harness. It should be plugged in every step. Check to see if the wiring has become frayed. Here’s How to Check for a Short (YouTube).
• Tires– On some vehicles, P0500 can be thrown if the tires have been swapped to a size that is different from the factory setting.

P0500 is the main reason that the code has been thrown almost all the time. The ECM/PCM could be bad. It is important to not look at the first place, but instead the second.

Because of their location, it is possible for the wiring harness connecting to them to fail. Replacing the wiring harness without first inspecting can lead to a costly mistake.

Fixed Price: P0500

The Wiring Harness should be inspected first. If everything looks great, you can then take a look inside at the VSS. Is there any visible damage to the VSS?

After you do that, (or before, if necessary), Useful scan tool) it’s time to test the sensor and see if the VSS signal goes up and down with the vehicle speed. If it doesn’t, replacing the sensor could fix the problem. If it does, you’ll have to test the rest of the circuit.

Conclusion

It can be difficult to diagnose P0500 problems in your GMC Sierra. Don’t skip checking the wiring harness first. Have fun!