maeliosa

Why is it sooo hard to find information about mode $06 (mode six, mode 6)? Almost every hit on google is some guy selling his "secret" information that'll "unleash the power of OBDII Mode $06!!!"

Well, after poking around a bit, I've figured it out I think. I got an OBD2 All-in-one scanner (ELM327 based) recently, and have been playing around with it. This lets you manually send data to the OBDII bus. Using this and the Honda mode $06 documents from https://techinfo.honda.com/rjanisis/RJAAI001_mode.asp, I was able to determine the following.

This is what I sent in hyperterminal (this is all in hexadecimal):


06 - indicate this is a mode $06 request
21 - request parameter identification (PID) code 21
(and for mode 6, PID is equivalent to test identification (TID))

The response:

4 - indicates this is a response
6 - to a mode 6 request
21 - for PID 21 (i.e. TID 21)
81 - indicates this is a result from component ID (CID) 1, and the test limit here is a lower limit
00 - padding? used for larger values?
09 - test value
00 - padding? used for larger values?
04 - test limit

One value needs more explanation, that value 81. This is one byte, and can range from $00 to $ff. The first bit, or most significant bit (MSB), indicates whether the test limit given is a lower limit (bit=1) or upper limit (bit=0). The lower 7 bits indicate the component ID (CID). So in this case, $81=0b10000001 in binary, the top bit is 1 so this limit is a lower limit, and the lower 7 bits indicate this is a CID of 1.

So, we open up the mode 6 doc for the 1998 Honda Civic, and you find the following:
For a TID of $21 and CID of $01, they tell you the following:


So our test result was 9, which when multiplied by their conversion factor gives 4.394529 mmHg, compared to a lower limit of 1.953124 mmHg. Which means, we passed the test, which is why the CEL/MIL lamp hasn't gone off. If the value reported was below the lower limit, then according to the mode 6 doc, a P1456 code would be issued and the CEL/MIL lamp would come on.

So, what do you all think of this? Is this right? It only took me an hour or so of tinkering around to figure it out. Why is it made to be such a secret?

If you look at a more recent model year, you'll find there are A LOT more tests that you can lookup. The mode 6 doc for the 2006 Hondas is 37 pages long, with all kinds of different tests, like finding out the number of times a cylinder misfired.

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Peoples

i think all information like this is meant to be a secret, people want to make money off of you any way they can. thats why it costs tons of money to buy specification licenses. Very cool, are you a programmer? Are you going to work on this any more. Also is this specifically honda?

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maeliosa

Mode $06 is part of the OBDII specification, so it is not Honda specific. It seems though that it is only available on 1997 and newer models. However, the number and type of tests available is specific to each make and model. Since the computer only gives you bytes of data, you need the data sheets for mode $06 from the manufacturer. techinfo.honda.com has all the Honda and Acura sheets, and I believe most of the other manufacturers have similar sheets available on their sites.

I'm not full-time, but I am a hobby programmer. I'm also a big promoter of open source, and there aren't any very good open source OBDII scan program out there now, in my opinion. Like I've mentioned in other threads, I'd like to write a complete, cross-platform OBDII scan program for the ELM series of scanners, but make it modular enough so that others could add support for their own scanners in.

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1998 Honda Civic LX
In VERY early planning stages now
---------------------------------
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joeyoravec

Mode $06 isn't really a secret. More likely you're experiencing a disorganized website. If you go to service.gm.com they have a Service Information tab with the identification and scaling clearly posted. Ford provides their information upon request to scantool vendors.

Unfortunately other OEMs don't play nice. Notice http://www.etools.org/i4a/pages/index.cfm?pageid=2407 which says Honda refused to provide their data to ETI, and tries to charge $5000 per year for scantool information.

maeliosa

I found the GM site in my searches, but even there it doesn't tell you how to dissect the response, i.e. byte three indicates test limit type and component id, bytes 4&5 are the test value, and bytes 6&7 are the limit value. I couldn't find a single mention of this anywhere in my search. Those GM pdfs were the only way I figured out how to decipher byte 3.

I don't claim to have made some breakthrough, or that it took a lot of effort. I'm just surprised that I couldn't find a single mention of how to decipher the mode 6 response, other than that bit from the GM pdfs.


Hmm, it seems Honda has the same information GM has on techinfo.honda.com site.

__________________
1998 Honda Civic LX
In VERY early planning stages now
---------------------------------
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jma

Where to get description of OBDII ( Mode06) codes
for Chrysler Intrepid 2002

jma

Lukeyson

This thread came up on another search I was doing for ETI - that link Joey had is now invalid.

This seems to be the same info for Ford:


Lukeyson

jma

TID 16 O2
TID 17 O2
TID 26 O2
TID 27 O2
TID 28 O2 Heater
TID 29 O2 Heater
TID 2A O2 Heater
TID 2B O2 Heater
TID 2C O2 Heater
TID 2D O2 Heater
TID 2E O2 Heater
TID 2F O2 Heater
TID 36 O2
TID 37 O2
TID 3D Catalyst
TID 3E Catalyst
TID 55 EGR
TID 56 EGR
TID 57 EGR
TID 58 EGR
TID 59 EGR
TID 5A EGR
TID 5B EVAP
TID 5C EVAP
TID 71 EVAP
TID 72 EVAP
TID 73 EVAP
TID 74 EVAP
TID 75 EVAP
TID 76 EVAP
TID 77 EVAP