RotaryResurrection

iTrader: (3)

I know there are many here who are intimately familiar with the stock PCM and it's function.

I am trying to swap in a different PCM into my existing car, but obviously the transponder in my existing keys will not work with the other PCM.

My dealers are claiming that they are unable to make my keys work with the new (used) PCM without the VIN of the car the PCM came from, and even then they are skeptical that it will work.

Will I have to locate a matching PCM/transponder key combination from the same car, or can I get this PCM I have set up to work with my existing keys?

Thanks in advance to those in the know. Some valuable information is going to come from my project IF I can resolve this PCM/transponder issue, and I will of course make all of my findings available to the community when the project is complete.

seikx8

You will need your original PCM in order to swap in the new one that is compatible with your year model. The WDS software will need to read your vehicle information block (this block contains the VIN and other data) and transfer them to the new replacement PCM. This will retain all the security and VIN info to work with your existing immobilizer unit to start your car.

If you replace the immobilizer unit & PCM as a set, the used PCM VIN will not match with your car frame VIN (this assume you can find the same immobilizer unit from the same donor car of the PCM). The used PCM contains the VIN info and it can be read out and that info can be used to get the PASS code (only mazda / authorized dealer have access to this service) to program the immobilizer unit if you don't mind having mis-match VIN from PCM to car frame.

Are you trying to swap in a different incompatible year model? or building a salvage car?

RotaryResurrection

iTrader: (3)

Thanks for the info. I am doing an AT to MT swap, thus the need for PCM swap.

The swap is currently in and running/driving in my car, running on my AT PCM. I am breaking in the new engine anyway so staying at lower rpms and short trips is not a problem until I resolve the PCM issue.

The dealer tech said that even with my existing PCM, VIN, keys etc. he could not make the other PCM work. He said he could not get the VIN out of the other PCM even though it is stored inside. He said some of the newer models will show you 4 or 8 digits of the VIN but not the whole VIN.

He said if I could get the VIN of the car that the new PCM came out of, he could *try* to make it work in my car.

I do plan to seek a second opinion from the other local mazda dealer, who I could not get ahold of all day long.

MazdaManiac

iTrader: (3)

Actually, there is a separate programming module that the QMD dealers car get that allows them to blast any PCM to work with the existing cluster and immobilizer.

dannobre

iTrader: (3)

All you need is your VIN...and the iDS ....I just did it.....so It can be done.

They need to access the " as built data" from Mazda....it's a bunch of hex #'s that correspond to the original PCM programming.

They enter the correct data and the new PCM takes the place of the old one..and you are good to go.

The remote info is stored in the keyless module and not in the PCM s it will be OK

dannobre

iTrader: (3)

The problem your going to have is the dash and a few of the other modules are different between the AT and MT.....so the MT ECU will likely NOT work with the AT dash...

Your wiring nightmare will likely be much worse than you think...

Sure you still want to do it

RotaryResurrection

iTrader: (3)

First, thanks for the replies. Seems a few of you guys are of the same opinion I am, that they should be able to handle this job. I think they are feeding me bullshit as a cop-out so they don't have to screw with it.

With regard to the "wiring nightmare" comment...

Just for reference, I do have the MT gauge cluster which I will swap after the PCM fiasco is resolved. I did not want to have it installed when I roll into the dealership, since the cluster shows the lower mileage from the MT donor car, and have a carfax mileage discrepancy show up on the car or some other bullshit arise.

Everything in the car currently works except cruise and DSC/TCS, I am using all the stock AT wiring except the engine harness and batter/starter harnesses, which are MT. I do have the MT main enginebay wiring harness/fusebox available, except for the fact that a certain member that I paid for the entire car's harness failed to give me the behind-dash wiring. However I have access to some dash harnesses from MT partscars so if necessary I can change that. If I get the proper dash harness I can change it out, and every wire in the car will be MT at that point...the car will no longer be an AT at all. If I can make a fuel injected rotary engine run on a metal bench (search youtube), I think I can make an AT car into an MT car.

Guys, this is just a car, and I am a rotary mechanic and builder of over 8 years now, so please don't give me the whole "ah, the At to Mt swap is impossible, its not worth the money, sell your auto and buy a manual, blah blah" spill. I have been swapping rx7s for years and have a good handle on what is involved, except for the additional PCM restraints in this particular platform. I will be the first in the country that I know of to swap a drivetrain and have everything work like stock, a seamless stock conversion. Sure plenty of people have done alternative engine swaps and standalone EMS systems but I have not heard of anyone doing it the way I am doing it. I am doing it this way to prove the naysayers wrong, and to offer a template for future swappers to follow.

It does not always make sense to sell or trade and get a manual car when you already have an auto. Some people get auto's for dirty cheap, such as myself. Even after I rebuild the engine and go through the 6sp transmission to be sure they are both good starting points, I will have less in the whole car and swap parts, with a new paintjob and new tires, than stock MT cars sell for, with drivetrains in unknown/questionable condition. Plus I will have learned something on behalf of the community that others will benefit from for the next 15 years.

olddragger

iTrader: (3)

sweet and appreciate your work dude. You are right auto cars are on the cheap now. get one swap it over and you could have a great club racer.
olddragger

RotaryResurrection

iTrader: (3)

I've been thinking more about this post so I thought I would quote it again.

This is exactly what I thought they could do. The car still starts, runs, and drives on the original PCM, and it takes 2 minutes to plug the new one up and then they should be able to transfer the data over. So why did the guy sit there and tell me that it couldn't be done? He was apparently the head tech of the dealership. He said the first thing the machine asks for is the VIN associated with the PCM he is trying to read, and if he doesnt input it correctly within a few tries, it kicks him out for 24 hours, or some such bullshit.

He told me they do not use the WDS anymore as it is outdated, they have another 3-letter acronym machine that they use now.

Why would it matter? I obviously do all my own work and would not need any work done by them except in such cases as this, and my car is well out of any warranty. The engine is not numbers matching at this point either.

MazdaManiac

iTrader: (3)

They call it "e-MDS" now.
I have to admit, I'm a bit fuzzy on the whole process - the guys that take care of that stuff for me do it with "no questions asked".
However, I'm pretty sure there is a separate "little black box" that is needed in addition to the e-MDS to prep a different PCM to work with the existing immobilizer and cluster.
It goes in-line with the cable from the e-MDS to the OBDII port and is done with the "new" PCM in the car.
The old PCM can be completely left out of the equation.

dannobre

iTrader: (3)

My PCM died....so I had a used one re-programmed to work in my car.

All they need is the " as built data" from Mazda...which is a sheet of paper with a bunch of hex values for different modules that the original PCM was programmed with

If you have used the other modules from the donor car and everything matches..it would be a simple job.

If the modules are different you would have to re-program the individual modules as well as the PCM so they will talk to each other...this can be a bit of a bitch...the instructions need to be followed to the letter to get it to work.
My power steering module was replaced at one time as well...and that took a while..we kept doing it slightly wrong and it didn't work...until we got the FSM out and followed the procedure correctly and then it was good

Mixing and matching will cause you greif unless you know exactly which modules are new...and old and program them all to talk to each other

If you are going to do this you need a good tech that knows how to use the iDS and has a brain..otherwise you can play for hours and get really frustrated as you can tell

seikx8

This tech has no idea what he is doing/talking about or do not have have proper access level where he is prevented from doing thing he don't know about.


I haven't played with the new version of software but they all work the same way regardless of the interface. The new software/application they use might have some protection feature which prevent theft or other like affect. However there should be a bypass mode that allow the tech to pretty much go into advance mode and can do whatever they way. The previous WDS I know has a passcode/mode which you can enter to go into the advance mode that allow programming individual modules without other additional check. From this mode you can read out the vehicle info block (128 bytes).

If you really want to do this yourselves, you can purchase a J2534 device and subscribe to the module programming service where you can download the self-serve Mazda Module programming software and you can do the PCM replacement yourselves. You can access the special function mode: 23198 that allow you to read/write the vehicle info block as well.

Like dannobre & MM said, you'll need to access a tech with knowledge on the software and be willing to do thing outside of the box.

RotaryResurrection

iTrader: (3)

I am not sure which modules you are talking about...

As it sits now, all the inside wiring and control boxes are what came stock on the car except for the AC amplifier which was replaced a year ago and worked fine just like that. And I have of course unplugged the TCM box, which was mounted in place of the clutch pedal.

The engine wiring harness, starter/battery harness, engine and all sensors, pcm, trans/driveshaft/shifter, steering wheel and pedals are all MT.

Electrically, the only thing that is changing is the PCM and engine/trans harness, at this point.

I have wired the starter circuit myself, from the ignition switch, to the clutch interlock switch, to the starter, in leiu of changing the dash harness to accomodate the addition of a clutch pedal at this time.

Depending on whether or not I can rig the cruise control to work properly with the existing AT dash harness, I *may* change it out to an MT harness later on. I am thinking that with the MT PCM in place and working (If that in fact happens) I could simply wire in the clutch pedal switch direct to the PCM terminals that are supposed to see it if need be to hopefully restore cruise control function, since my AT dash harness will not have that plug or wiring in it.


I talked to another dealership today and they seemed much more confident that they can make the MT PCM work in my car with my keys. I have an appointment tomorrow to go and see what they can do with it. Hopefully if the tech "has a brain" I may be able to talk them into getting the MT cluster mileage programmed as well.

MazdaManiac

iTrader: (3)

You need the two immobilizer modules from under the glovebox and the key coil from the ignition cylinder.

G3tR3DDY2GR3DDY

iTrader: (8)

oh i think i still have those... call me if you can be rational, kevin. i wanna see you get it working

RotaryResurrection

iTrader: (3)

UPDATE:

took the car to another dealer today. The head tech was real cool and seemed way more knowledgeable. He didnt think it would be any problem, but I take it that he had a few issues with the procedure once he got into the computer. It took him about an hour of fooling with it to get it working. The guy was cool and when he was done, we got to BS'ing about rotaries and he found it amazing that I had built the very engine in that car. We got to talking about rotaries and I think he was learning a few things, then it was closing time. We walked back to the service writer together and he told her to give me a better price than she was going to charge me originally. IT wound up costing me a whopping $67 for the service of getting the PCM working with my key and in my car.

He said he didn't need anything regarding the other car's VIN, he just left that previous info in the new PCM as it was. He said that each module is set up to communicate only with the other stuff that it was built with in the car, and so as a result some of the extra **** might not work right in the car. He got everything working right except ABS and DSC/TCS.

The cruise control actually works now, in spite of the fact that there is no clutch pedal switch for the cruise circuit (I am pretty sure there should be).

I have manually tested (lol) the fact that the TCS and ABS do not function at all. He said that if I got the matching modules to the donor PCM, they might work again, but he did not think he could lie to the system and make my originals work.

I am just fine with the TCS/DSC not working but I would like to have ABS, so I might look into that further.

I am also getting a random p0300 misfire code while driving at speeds higher than 60 or so. I have not gone WOT with the car yet due to engine breakin. I have put in fresh brand name 93 octane and still get the flashing CEL at times. I swapped over the whole ignition from my old engine which never gave me any codes. The plugs are sandblasted clean, the coils and wires were from my old engine so I know they work fine.

I inquired about reprogramming the MT cluster's odometer to match my existing chassis miles, and he said there was no way they could do that at any dealer...they have to order a new one, and the mileage is input onto the new one by the manufacturer when it is ordered. However I have installed the cluster and it works 100% other than the lower indicated miles.

Bottom line, I have a 95% functional stock AT to MT swap in operation at this time and total cost was in the $3k range including all parts, rebuilt engine and new synchros in the transmission.

dannobre

iTrader: (3)

Glad they got it working....They should be able to re-program the ABS stuff as well...you might need to re-use the original cars VIN for bits of the as built data?? for those modules?? There should be someone at techline that knows how that works..get the Dealer Tech to phone them and see what they say..

TopGear8

iTrader: (3)

i might have some of the ABS stuff as well.. not really sure what all you would need. lmk

MazdaManiac

iTrader: (3)

The P0300 is usually set because of the ESS.
Try resetting the profile.
You might want to check for debris on the ESS and clearance between the sensor and the trigger wheel.

RotaryResurrection

iTrader: (3)

well, I dont think that would help me any more than what I already have.

My ABS all worked fine until the PCM swap, so another random ABS module wouldn't help me. I think I'd need to track down the ABS module that was originally mated to this donor PCM to do any better than what I have now.

I was also thinking about the misfire being from the crank sensor, however I have not seen any shims in use on factory engines so I did not think it should be necessary. I will check the clearance later and either use shims or file off material to change it if necessary.

I think I need to source myself an updated/upgraded MT starter and then I should be good to go...this thing seems to crank a little slow for my liking, like 200rpm slow.

tdiddy

Dannobre and I both had issues with misfires. Granted our engines are not stock but I had a couple issues when I was stock. Cleaning & shimming the ESS fixed all my problems.

RotaryResurrection

iTrader: (3)

Thanks for the suggestion Jeff.

Well, I pulled the crank angle sensor off and it looked clean and fine. Teeth on the crank trigger wheel are also fine and clean. I went ahead and switched my sensor with the one from my old engine (that had no issues) and also used 2 0.015" shims to push it away from the wheel a little. Before removal, it had about 1mm of clearance, as did my old auto engine.

I cleared the code and went for a ~5 mile drive which was a mix of low speed and cruising speed and got no code yet. I'll have to keep an eye on it for the next few days to see if it returns. I dont understand why the shims seemed to have helped, but meh, whatever.

MazdaManiac

iTrader: (3)

Its not a real misfire. Its the PCM losing track of the crank position.
The PCM wouldn't know a real misfire if it led to the car burning to the ground!

I've had some of the most jarring, bone-shattering misfires (like when my water/meth system freaked out the other day) and there was no code at all.
However, it used to set a P0300/P0301/P0302 when it is running smooth as glass.

Ventovic

I have a 2004 rx-8 and have swapped pcm from another automatic 2004 rx-8.....is there any thing else suppose to be done to get it to crank spine over or was I suppose to do something before I swapped them......want crank at all all dash lights come on and all the little noises come on with switch but that's it, it just sits there.....any help would be much appreciated.

dannobre

iTrader: (3)

You will need to reprogram the PCM with the as built data to reconfigure and recalibrate the CAN communication between modules.