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 RussMasterTech Your Own Question
RussMasterTech
RussMasterTech, ASE Certified Technician
Category: GM
Satisfied Customers: 791
Experience:  19 years of GM Dealership experience. ASE Master with L1 and GM Master Certified in Electrical
9377736
Type Your GM Question Here...
RussMasterTech is online now
A new question is answered every 9 seconds

2000 gmc: speedometer..instrument..mechanic friend..diagnostic test

Resolved Question:

The speedometer on my 2000 gmc savana cargo van isn 't working. SPECMO says the instrument in the dash checks out good. A mechanic friend ran a diagnostic test on the engine and said the computer is reading the speed. What could it be?
Submitted: 7 years ago.
Category: GM
Expert:  RussMasterTech replied 7 years ago.

HelloCustomer

 

If the green wire between the VCM/PCM is shorted to ground or power, the speed signal would not be received by the IPC. I'll send you the schematic. There's not much else it could be if the VCM is seeing the signal. Either the wire is damaged between the VCM and the IPC or the VCM is defective. There are a lot of problems with corrosion on those VCM's.

 

Here's the schematic.

 

Object Number: 521734  Size: FS

RussMasterTech and other GM Specialists are ready to help you