Thursday, February 17, 2011

NB Miata - OBD Mode 5

If you thought Mode 4 was simple, Mode 5 is, in some ways, even simpler.  At least a Mode 4 request causes something to happen.  Mode 5 requests only return information, and that information never changes!

Mode 5 is meant to return information that is used for oxygen sensor monitoring.  In the NB, only the following TIDs are supported:
  • 00xx - this is the TIDs supported TID.  It must be two bytes, but the second byte can be anything.  The reply tells you that only TIDs 1 and 2 are supported
  • 0101 - returns the rich-to-lean threshold voltage for O2 sensor 1
  • 0102 - returns the rich-to-lean threshold voltage for O2 sensor 2
  • 0201 - returns the lean-to-rich threshold voltage for O2 sensor 1
  • 0202 - returns the lean-to-rich threshold voltage for O2 sensor 2
What makes this mode so uninteresting is that all you can do is request the above threshold voltages.  What's more, they are all the same (0.445V) and never change.  Yawn.

Next up, Mode 6.
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1 comment:

  1. NiaXiAugust 17, 2013 at 1:36 AM

    Hello J. Wong! I'm working on a diagnostic scanner myself. Code is written in C# and the hardware is ELM327 based. Most of the things have been done. I am, however, stuck at fuel pressure test for a vehicle. I need your help for that purpose. I cant find your email so I'm posting here. Please leave me an email at aknwajood@gmail.com so that I could further tell you the commands I'm stuck in. regards and keep up the great work :)

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