Blink transmission codes = 2006 Mazda 3

Hi sorry if this has been asked elsewhere but I'm trying to get something figured out without much luck so far. 2006 Mazda 3 2.3 liter, about 51k, maybe 52k miles on it. Drove it all day yesterday and it was just fine. Turned it on this morning, and when shifting into reverse it just went KERCHUNK. Also clunks when going to drive, but not as much. The car shook like I get hit from behind, Check Engine Light and AT light both came on. Drove it around the block and it definitely seems to be in limp mode. Have done some reading elsewhere on the webs and from what I understand it's probably more electronic in nature, so on a whim disconnected the battery, let it sit, and reconnected and turned the car back on. No change. I want to see if there's a way to get the transmission codes to blink out so I can figure out what's wrong before I get it towed to the dealer and they try to talk me into a new transmission (from what I've read, that's the usual thing they do). Any insight out there would be greatly appreciated.

It's obd2, you can't blink transmission codes. You need a DTC reader... Most autozones/ o'reilly's will pull codes for free

You'll have to forgive me, as this is probably a dumb question, but....I thought OBD2's were mostly for emission-related problems. Can *any* OBD2 scanner read DTC codes or just particular ones? I'm asking because I'm not particularly inclined to drive the car to an AutoZone in case there's something seriously wrong, or make a not-too-serous problem worse than it has to be. I'm seeing some cheapies at Walmart for like $30 so wondering if one of those will do the trick.

If the transmission is messing up because of something that is a Mazda-specific DTC(think transmission codes) then it will not tell you what exactly.

Rather it will show up as a P0700(generic transmission DTC). There may be a few others as well.

Those cheap scan tools will only read the generic OBDII codes... which will tell you about 96% of everything you need to know... except for stuff like body control codes, transmission-specific codes, etc etc. It's pretty redundant when it comes to engine specific codes(ECM) and will do 99% of those.

It could be something as simple as a speed sensor or crank position sensor, or it could be a failing solenoid in the transmission or something physically wrong inside of it. The crank sensor would show up as a problem by not displaying RPMs on the gauge, but you get the idea... the transmission depends on MANY inputs from the engine sensors to choose which gear to go in.

I recommend you go to a parts store, scan it for free, and see what it comes up with. If you get the P0700 then you will need to take it to a dealer, or someone that has a scan tool capable of reading the factory specific DTCs in the PCM or TCM(I forget if Mazda has a separate ECM+TCM or both in one in a PCM).

PCM = powertrain(both engine + trans)
TCM = transmission
ECM = engine

I use a Matco Determinator at work and it will at least pull codes from all the different Mazda computers no problem, what that scan tool lacks is two way capability in stuff like actuating solenoids via the scan tool to see if they respond... it does or does not have these abilities depending on the revision of the scan tool and support from the factory... it's more friendly with domestic built crap like Chrysler and GM.



Shifting harshly like you describe can be something as common as the TCM not knowing which gear your gear shifter is selecting. Does the dash tell you if you are in drive or reverse like it should? (I honestly don't know if it does.. I have a 5spd). This is usually a good indication that you have a broken wire in the shifter assembly or the shifter itself is not making contact and needs replaced. Always check for +12v and or 5v reference where applicable, you'll want a factory wiring diagram to know which wires to test to make sure you don't replace a shifter for no reason.

I just recently replaced a floor shifter on a Suzuki Vitara and it did the exact same things you mentioned... slamming into R and D, slipping all the time and in limp mode. It had a wire ripped out of the shifter's circuit board.

Thanks for the info. Sounds like some good stuff in there. Will get a scan on it and take it from there. Crossing my fingers it won't be too bad. I'll post again if/when needed.

Okay an update here: I borrowed a OBD2 scanner off a buddy. Got an U0101: Lost Communication with TCM. I've seen this in other threads so it appears to be a common issue. I don't know automatic transmissions all that well, but from what I gather, in layman's terms, the car doesn't know what gear it's in. Super. Anyways, the most common thing I've read about it is, get it to a dealer, plunk down about $600 for the TCM and whatever the labor rate is for a couple hours, and if they're nice they'll waive the diagnostic fee. Is this really the best way to handle that? I've seen one or two other guys mention that it's something that you can do yourself (I got a brother who's a little more mechanically inclined than I am, and works for beer), while others say it has to flashed/programmed/etc'ed at the dealer.

Oh to answer one of the above questions, the dash indicator doesn't show which gear I'm in. I don't know if that goes without saying for this problem or not.

MsideRuss said:

Okay an update here: I borrowed a OBD2 scanner off a buddy. Got an U0101: Lost Communication with TCM. I've seen this in other threads so it appears to be a common issue. I don't know automatic transmissions all that well, but from what I gather, in layman's terms, the car doesn't know what gear it's in. Super. Anyways, the most common thing I've read about it is, get it to a dealer, plunk down about $600 for the TCM and whatever the labor rate is for a couple hours, and if they're nice they'll waive the diagnostic fee. Is this really the best way to handle that? I've seen one or two other guys mention that it's something that you can do yourself (I got a brother who's a little more mechanically inclined than I am, and works for beer), while others say it has to flashed/programmed/etc'ed at the dealer.

Oh to answer one of the above questions, the dash indicator doesn't show which gear I'm in. I don't know if that goes without saying for this problem or not.

Click to expand...

That code really doesn't mean anything at all in the OBDII module. You need to get a factory capable scan tool to read the TCM... there will VERY likely be more specific codes in there, which will tell you which direction to go.

Generally transmissions won't just up and go into limp mode for no reason and need replaced... it lost a signal to/from something and won't let it operate normally.

I worked at a Chrysler dealership for 2 years... and I'm sure you've at least heard about how aweful their transmissions are. I've replaced a couple... but 95% of them it is something like the solenoid pack, one of the speed sensors, or a shifter as I mentioned earlier.

The fact that you're not seeing which gear you're in really makes me want to put my money on you needing a new shifter assembly. This is stupid-common in many modern cars.... I've easily replaced at least 50+ floor shifter assemblies in Grand Cherokees/Commanders/Malibus/Cobalts/etc. I just did one in a 2008 Lincoln MKZ last week... which IIRC is based on the Mazda3 chassis... surprise surprise. Albeit it had the V6 but you get the point.

If you really wanted to do it yourself and have a super useful tool for future use... you could get this scan tool which is laptop based(obviously supply your own laptop):

www.autoenginuity.com

You would need to buy the $250 base "ST-06" which is the hardware you need to connect the laptop to the OBDII port, and basic software to read the OBDII module for your basic powertrain and emissions codes. You will be able to look at stuff like timing and O2 sensors, rpms, etc etc. You can datalog stuff as well which is awesome for troubleshooting weird stuff.

Then add on the "enhanced" Mazda package for $150 and you can access all of the factory Mazda modules like the TCM, TPMS, ABS, TCS, etc. Here is the direct link to all the factory modules that are supported: http://www.autoenginuity.com/Mazda-All-Systems-List.html

It's a very nice scan tool, I use it at work and while I don't use it that often(the Matco Determinator is more portable and quicker for 95% of the cars... so it just sees more use in a fast-paced environment)... but it has come in handy multiple times. I use it to read the weight sensors of Mazda CX7s all the time... those damn things go out of calibration all the time, the Determinator doesn't register that IIRC.

The AutoEnginuity supports two way communication as well.. you -should- be able to command the various solenoids in the transmission and feel the car respond to them. Actuate the L-R solenoid and it should go into gear, actuate the 2-4 solenoid and it should be in a taller gear, etc etc. I've done this many times with Chrysler vehicles to determine that solenoids are functioning fine, and ultimately finding out that something isn't commanding them to do what they need to do... whether it is because of a broken wire, or failing TCM or whatever.


Hope that helps some.