How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Jeremy Your Own Question
Jeremy, Certified Truck/Bus Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 3362
Experience:  ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, EPA 608/609 HVAC Certified, Steering/Suspension and ABS/Brakes Technician
Type Your Medium and Heavy Trucks Question Here...
Jeremy is online now
A new question is answered every 9 seconds

Know anything about c5500 chevys, vss problem, 2007 c5500,

Customer Question

know anything about c5500 chevys, vss problem
JA: What is the model/year of your GM?
Customer: 2007 c5500
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: throwing code p0502, scanner sees speed, speedo drops out, vss is good
JA: Just to clarify, what's the exact code? And have you tried to reset it?
Customer: p0502 cleared and comes back
JA: Anything else you think the mechanic should know?
Customer: nope
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Jeremy replied 1 year ago.

My name is ***** ***** I will assist you with your question today.

I'm an independent contractor and I don't get paid until a rating has been made.

We can go back and forth as needed to help resolve the issue you are having. Follow ups are free after ratings, so rate in confidence!

Are you sure the computer is seeing the VSS? As in you are on that parameter itself and you are getting the good signal? I ask because the signal comes from the VSS and the wheel speed sensors in the computer. If the VSS is for certain good and not dropping out, then there is a harness issue between the ECM and the cluster. The ECM could be sending the signal, but the cluster is losing the signal and returning that to the ECM which will throw the code.

CLICK HERE for the diagram to check that circuit.

2 other issues are the signal can have "noise" where it will still read, but drop off for a milisecond and come back up to throw the code. That will be a harness issue if that is the case and to find it, you will need to ohm test and do a wire wiggle check down the wire.

The last is there could be a issue in the PCM causing this to happen.

The Chevy trucks are bad for having harness issues on the VSS circuit at both the connector for the VSS and at the back of the cluster.


You want a 5 star service and I want to provide a 5 star service. Please consider that I don't know your skill level as well as I can't see, touch, smell, hear the vehicle/machine in question. Please provide as much detail as possible and I will provide as much back.

Once an answer is provided, you should see a rating screen. Please rate my personal service to you. The ratings are my personal feedback,

they are not the site feedback.

Thank you for allowing me to assist you through Just Answer!

Customer: replied 1 year ago.
cant open the wiring diagram
Expert:  Jeremy replied 1 year ago.


I'm not sure what happened but try that.

I didn;t get a response notify either so I apologize for the delay.

Expert:  Jeremy replied 1 year ago.

I see you viewed this and this is still showing as an open question due to no positive (3 stars or more) rating.

Were you not pleased with my service to you or is there a rating issue? Please let me know if you still need assistance with this, if there is a rating issue, and/or you need more time to respond.

I like to make sure all my customers are satisfied since you did pay a deposit for me to assist you, whether I’m paid by a positive rating feedback or not.

We can continue where we left off or start over if needed. Also, if you need diagrams, instructions, etc please don’t hesitate to ask.

Customer: replied 1 year ago.
that is not the correct wiring diagram for this truck
Expert:  Jeremy replied 1 year ago.

That is the only one Chevy has for the 2007 C5500.

I'm going to opt out for someone that might have it and close the link since it isn't the one for your truck. You have something changed on yours that the system is not showing.

Good day.