OBDII Communication problem

Tiny
LCATMAN1
  • MEMBER
  • 2012 MAZDA 3
  • 4 CYL
  • 2WD
  • 28,000 MILES
My mechanic hooked up the N.Y. State inspection computer numerous times to my car, but kept getting a noncommunication error message.
Tuesday, September 14th, 2021 AT 1:02 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,355 POSTS
Hi,

Do you know if he is getting power to the data link connector? Pin 16 should have 12v at all times.

If it is, then what needs to be done is the have the CAN scanned for diagnostic codes. CAN stands for controller area network. Basically, all computers/modules are tied together via a few wires. If there is a breakdown in communication via the CAN bus system, that can prevent communication.

Here is a quick video showing how it's done:

https://youtu.be/InIlnsjOVFA

I attached the schematic of the CAN system below for you to review. I had to cut the pic in half to make it readable for you, but I did overlap them so you can follow from one to the next.

Take care and let me know if you have other questions.

Joe

See pics below.
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Tuesday, September 14th, 2021 AT 8:40 PM
Tiny
LCATMAN1
  • MEMBER
  • 2 POSTS
Thank you for the quick response. I failed to mention that my mechanic attempted another inspection procedure using the same equipment on another vehicle, a Ford van, and that was successful. I am going back to see him today and try again.
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Wednesday, September 15th, 2021 AT 4:12 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,355 POSTS
Hi,

You are very welcome. If there is something I can do to help, please let me know. Also, let me know the results of this attempt and if the mechanic is getting power to the data link connector (DLC). If there is no power, that is what we need to check. If there is, based on design, I have a feeling there is an issue within the CAN-bus system.

At that point, I would suggest having the can-bus scanned to see if there is an indication of a breakdown in communication within the network.

I look forward to hearing from you.

Take care,

Joe
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Wednesday, September 15th, 2021 AT 7:36 PM

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