ODBII Mode 6 Tests - What do They Mean?
 

Hi,

I'm having trouble determining an ODB II Mode 6 ($6) test result. Here's exactly what what the code reader says:
ODBMID $71 FAIL
TEST ID $81
1C64 NOT >= B4DF
1C64 <= 7FFF

Does anyone know where I can find a list of the mode 6 test numbers and what they mean? I've found some mode 6 information on Google, etc. but I can't find anything that lines up with these numbers.

Thanks.

Does anyone have any idea how I might go about figuring out how I might find this information? Any suggestions welcome, vague or otherwise.

Does the reader support CAN-bus?
Doesn't look like a typical result you should receive.
Auto stores in the US will use their readers to scan for codes, for free, and tell you what they are.
Not sure if Canada has a similar auto store that'll do that, but it would be nice to see what another reader says (that supports CAN).

mode 6 is reported in hexadecimal format if i remember correctly. The higher priced scan tools will translate the hex into a more reader friendly format.

The Test ID will tell you what test your looking at, then there are the minimum and maximum specs. Then you have what your last test result was.

I'll need to do some digging to see what test your looking at. Are you trying to determine your cat converter test result?

Thanks for the responses.

I went to a Canadian parts store that will let you use their OBD-II code reader. It didn't help, and could only tell me the same information as my $30 Princess Auto (Harbor Freight equivalent) reader. I borrowed a friend's better ODB-II code reader to receive the mode $6 results, but it's a bit disappointing as it doesn't seem to be able to do the O2 sensor tests. I believe it supports CAN bus. The way the reader worked, I had to run a monitor test and after a period of time it can obtain results. In case you're wondering my CEL is P0420.

I've run the catalytic converter test OBDMID $21/testid $81 as per http://www.finishlineperformance.com...4-08-1924g.pdf. That test showed all zeros for the result, so I'm not sure if I can trust the reader's values.

I'd like to determine my cat test result, but the first test results I posted occurred when the CEL came on. I'd like to know what it means because I'm assuming its somewhat significant.

If you cleared the codes anytime with any of those scan tools, you will clear all Mode 6 data. So you will have to drive the car again and hope the monitor runs.

I recommend a steady state cruise down the highway for about 15-20 minutes. If you can bring your scan tool, you'll be able to see if the monitor has passed while driving.

Ok I've got a little more time to reply.

The more expensive scan tools will automatically translate your Mode 6 data for you using the manufacturers data. I have an autoenginuity and it does it for me.

BUT if your car has a P0420 code already, that means the cat is already out of MODE 6 test range, so has failed and that is why the check engine light is on. The Mazda bulletin that you referred to is to check the cat converter condition without having a P0420 code. They want the techs to see if the cat is failing, without waiting for it to fail within the Mode 6 parameters.

So to make it easier, if your P0420 code is on and you want to double check it, I would clear the code. Then perform a drive cycle, get the cat monitor to run. If the code comes back, you have a bad cat!

Good to know that I need to run the tests without the code being active. The values posted in the first post occurred when I was driving without a code with monitor mode on. When I was almost done the trip/monitoring the code came on. Would the CEL appearing have caused the cat monitor to show zero values?

Nope, it's supposed to retain the last test results. Don't know why they went to zero, but could be your scan tool miscommunicating?

I have some new results. That original mod $6 test now seems to pass. I'm finally failing the "right" test. OBDMID $21, Test ID $80

I also have a pending P0111, which seems to related to the intake air sensor. Kind of weird, but I found another post where someone received this code after swapping in a mid-pipe, so it sounds like there's a correlation.

Looks like it's new cat time...

Mazda replaced the cat under warranty. The pending P0111 never came back, but the P0420 reoccurred repeatedly.

Before having the cat replaced I had someone I know driving behind me and they commend that when I accelerated hard there was smell and visual smoking.