edited 3/26: added addition KAM procedure, also formatted it for easier reading, removed some excess.

Hey guys,

Alright I seem to frequently be running into people suggesting you clear the KAM and/or NVRAM by holding the odometer/trip reset button and when it says test bla bla bla.

First of all, the only way to clear a code is with an OBD scanner or disconnecting the battery, CEL codes are NOT stored in KAM or NVRAM they are stored in basic memory in the module which they are set (PCM, TCM, ABS HU/CM, etc..). No power to the module with the code = no more code.

Here is how you clear your memory, also some reasons to clear each memory:

NVRAM (Non Volatile Random Access Memory)
NVRAM is a rather unique feature. The system memorizes the profile of the eccentric shaft plate on the e-shaft pulley. It basically knows how the e-shaft spins, on an individual basis, 2 cars NVRAM will generally never be absolutely identical, they're pretty close to unique.

As you'd imagine with such a specialized system you wouldn't want this information relearned and forgotten very easily, relearning the profile isn't a short process (drive cycle, dont worry you dont do anything special to relearn it). So this info is kept in a special area of the PCM it CANNOT be cleared in any way EXCEPT the proper procedure, you could disconnect the battery and do a jig for a year and it won't erase.

When/Why should you erase the NVRAM?
Realistically there are only a few times, generally the only times it's really needed is when replacing a motor since you'll be installing a new e-shaft position plate. Sometimes you'll also repair a misfire, yet the misfire code will return even with you not noticing anything, in those cases clearing the NVRAM will sometimes help. Also during PCM replacement it's good to clear it.

How do you reset NVRAM?
Here it is straight from mazda:

NOTE:2004-2008 and 2009 and later model year procedures are different.

2004-2008 Method

1. Turn ignition switch to "ON" position, but do not start engine.
2. Pump the brake pedal at least 20 times within 8 seconds after the ignition switch is turned ON.

NOTE:
Manual transmission equipped vehicles produced after VIN 40132647 and automatic transmission equipped vehicles produced after VIN 40132607 or vehicles with PCM updated to "L" calibration or later can confirm the clearing procedure was performed. If procedure was successful, the oil pressure gauge needle will move to right of center slightly (nearer H).
Vehicles produced prior to these VIN's or vehicles without "L" calibration do not have an indicator to confirm the clearing procedure was performed.


3. Drive vehicle and confirm misfire related DTCs are not stored.

NOTE:
If the malfunction cannot be corrected even though the procedure was successful, the eccentric shaft position plate may be damaged. Inspect the eccentric shaft position plate. Refer to MS3 online instructions or Workshop Manual section 01-40 ECCENTRIC SHAFT POSITION PLATE INSPECTION and repair as necessary.

2009-2011 Method

1. Record customer radio station presets (FM1/2, AM, SAT).
2. Disconnect negative battery cable for a minimum of 1 minute.
With negative battery cable disconnected, depress and release brake pedal one time.
3. Reconnect negative battery cable.
4. If equipped with DSC, perform the STEERING ANGLE SENSOR INITIALIZATION PROCEDURE located in MS3 online instructions or Workshop Manual section 04-15.
5. Input customer radio station presets.
6. Initialize power windows. Refer to MS3 online instructions or Workshop Manual section 09-12 POWER WINDOW INITIALIZATION PROCEDURE.


KAM (Keep Alive Memory)
Keep alive memory is not named because it keeps the car alive, rather it's named after the way it works. When you remove the battery terminals from the battery you'd assume all power in the car is lost right, hell your clock resets so the PCM must too, right? WRONG. KAM is saved by "Keep Alive" power, reserve battery power if you will.

KAM generally doesn't store very important stuff, other then the airbag operating on KA power they dont store anything in the KAM tho they just use the same reserve power. The main thing KAM stores are things like fuel trims etc. It's useful to reset KAM when you have lean/rich codes where the fuel trims have been able to reach 25%. It takes a while even after repair for the fuel trims to go back to proper levels, if you clear the KAM it will reset them to 0%.

How do you reset KAM?
Two easy ways, disconnect the battery and leave it like that for at least 10 minutes, sometimes longer. To expedite the process disconnect the battery and hold down the brake pedal, itll drain the KA power quicker. This will allow all codes to clear and KAM to clear.

After some research, at this time, it seems pulling the Room Fuse on the interior fusebox will also clear only the KAM. Not 100% sure yet, but pretty close.

-----------------

So what is this instrument cluster/odometer test thing people have been throwing around? The answer's right in front of their face, as it says it is a "TEST" and since it's in the Instrument cluster it would be.........the Instrument Cluster Input/Output Check Mode.

What is the IC Input/Output Check Mode? It's a quick and easy way to test all the electric meters/sensors/lights etc in the IC.

Here's a link to a larger description:
https://www.rx8club.com/series-i-do-yourself-forum-73/diy-diagnostic-outputs-155947/

YOU CANT CLEAR ANY PCM MEMORY WITH THE ODO/TRIP RESET BUTTON. If you want i can explain how to test each on of those things... im still searching for where in the FSM it says the odometer can reset NVRAM, because im sure mazda would like to repair it.

Thank you and good night,
kevin.

 

So

Yeah...

Dumbing down question?

NVRAM reset will help to.... New Engine, Misfire, New PCM?


KAM: Lean/Rich Fuel?

 

Thanks for the clarification teknics.
this should clear any questions and/or confusions.

Also, if anyone is interested in the various outputs that teknics mentions with holding the odometer button, I made a DIY for that:
https://www.rx8club.com/showthread.php?t=155947

 

Simplified/Cliff Notes

Reset NVRAM when: E-shaft pulley is going to be different (aka new engine, new shaft, new pulley), after misfires (wont always have any effect, but to skip the details it helps sometimes), and with a new PCM.

KAM: Rarely a reason to reset unless experiencing issues after a repair generally something dealing with fuel trims, but also random other things. Basically if you know 100% you fixed the problem but are having weird issues try resetting it.

kevin.

 

we need to link up and write some helpful stuff and correct all the things around here lol.

kevin.

 

Alright Kevin, thanks for answering my question


I'm putting an Agency Power Undercrank Pulley on in a couple weeks.


So I'm assuming NVRAM?

 

Yea I'd clear the NVRAM definitely if changing the main crank pulley.

kevin.

 

Awesome thanks so much for my "noobish" questions Kevin

 

very useful info teknics. thanks.

and i really wanna take my car to u lol. hopefully when its warmer out.

 

Hey Kevin,
I know Mazda's OEM Coils are for the suck but I have P0300 and was thinking, should I reset KAM?
Will that help me out in any way? or I just need new Coils... Again! gerrr

 

my car keeps giving me the code P0420 and it sounds like its misfiring but the code is for catalyst think the first reset might help me? i see service bulletins saying cars below 2005 need a PCM reflash to get rid of this code but mine is a 2007

 

I might clear the NVRAM for the hell of it, and might as well clear KAM too so the CEL resets.

If it comes back look deeper into it. Generally if its a constant problem itll be there evn right after doing the memory clear.

Kevin.

 

So does pulling the room fuse do anything?

 

thanks for this Kevin!!

 

p0420? If the car feels sluggish i'd think the cat may be clogged, the damage to the cat could be caused by misfiring in the engine. That code normally is only set when there is a measurable problem so clearing it wouldnt do anything.

I'd get the cat checked out and check through your ignition (plugs, wires, coils) at least to start.

kevin.

 

room fuse pulling will reset your clock and turn off your interior lights.

you can drive around with the room fuse blown/pulled so I'd imagine it won't help reset anything. Unless im thinking of another car but i think thats how the rx8 is. Room fuse gets blown a lot when people's driver's visor breaks and they rip it off, which cuts the wires and if they touch together they short out and blow the room fuse.

kevin.

 

and unless this has changed in the last flash it will erase you trip meters and clear the fuel trims.

that was a good tip from racing beat that stopped the bat pull method for fuel trim reset.

beers

 

hmm if it erases fuel trims then it's clearing the KAM. If RacingBeat said it i tend to believe it, i'll look into it to be positive tho.

kevin.

 

Good info for those who don't know.

Great post.

 

Interesting...

 

lol i was just opening up my wiring diagrams. Time to grab the rx8 PCM stuff now..

edit: well decided to use quicker resources and got you guys a full list of the room fuse circuits in a handy screengrab, i think i blocked out all the web addresses and stuff, but honestly if you see anything you obviously know you shouldnt be seeing dont try to access it, ok? thanks. (plus youll get to see the cool interactive wiring diagrams i get to use )

in case you dont feel like clicking the image, everything on the room fuse circuit is:
engine control
instrument cluster
TPMS
DRL
Heater and AC
AT Controls
Rear window defroster/trunk light
interior lights
audio system
nav system
keyless control module
dimmer mirror
power for the DLC

I'll trace exactly what "engine controls" is but im guessing it provides the power for the memory, so we now can be sure pulling the room fuse may in fact clear the KAM, close to 100% but not until i go over the PCM diagrams (more proprietary info ftw lol)

kevin.

 

Wow... pretty!
I'm jealous now teknics.

 

Great info Kevin!!

Perfect timming for my engine update.

Regards,

Nick

 

you should see all the great features. the best is "power flow" i can watch in the wiring diagram the flow of current with the key in the off, acc, or on position and what happens when a switch opens or closes etc.

plus i can click where a wire enters a connector and up pops the whole connector diagram with full pinouts, colors, details on where it goes etc. Also in the screengrab youll see lots of arrows saying where the wiring diagram is continued, click that and it sends me to that specific diagram, no hunting thru pages.

we have so many resources that apparently so few techs utilize.

kevin.

 

you used to be able to clear the fuel trims with the brake dance or the key / left audio button push.

but something happen with the r flash a while back. and it became the bat pull or the room fuse pull.

btw, thanks for you insight here!!!!

beers