You guys out there are the only experts I know on automatics like this that may be able to help us - or know someone you could ask that might know the answers. We have a Mazda that is running the dreadful CD4E and the same motor (2.0) that many other Ford products used. We bought the car to fix up for a niece that needed a vehicle and are stumped as to what is the real problem. It is a 626 Mazda - almost identical to Ford Probe - and uses a less beefy version of the CD4E than my my Escape / or a Contour, and other Fords. We first paid $800+ on a used trans that was supposed to be good and put it right in. Nothing changed. Old unit used to at least work in reverse and low so tried to get money back because the used one was utterly worthless. But sleazy salvage guy told us AFTER we found it was junk that he gives no warranty. (If you are getting used like we do watch out for guys like this.) We went through old trans with rebuild kit and all looked fine but we still have not gotten it to work right.

After the car sat, the battery went stone dead and when we jumped it it activated an alarm that we did not know was installed and it killed motor from even starting. When we pulled dash we found there were actually two seperate alarms put in over the years and we had remotes for neither. We pulled all we could see and hooked up original wires but we still have the trans issue. My poor brother has pulled, torn down, and tried 2 different trans - 3 times each and checked all parts and double checked all instructions in rebuild book for CD4E (Mazda calls it the LA4A-EL) and everything looks like it should actually work in both. Bought new torque converter to even rule that out.

With car in the air on lift and started - if you put in reverse it will move tires backwards, but if you then go in any forward gear you get nothing. If you then go back to reverse you get nothing from that gear again either. One other very odd issue is I have a very expensive machine that can do everything, not just code read OBD (engine lights), but also airbags, ABS, everything. You can even do real time readings of any sensor on any of the computers in the vehicle. When you hook it to this car it asks you to check ground and turn key on like computer is not on, but car is running. We thought computer may be bad so I bought used computer and put that in and same issue. Have never, in all my years, seen a computer that lets motor run but reads as not active when tested. May be another disable portion from the stupid alarms we took out, but have not seen or heard of one that kills trans activation and wondered if anyone out there had heard of something like this. We found another used trans that has been (supposedly) tested and does have a warranty at another salvage yard but I spent $800 on the first (and a few hundred on the rebuild kit etc) and I am worried about this.

These are the issues I hoped some of you guys with a lot of time seeing the weirdest of the weird could maybe help me with. I know it is a lot to ask but most of you guys seem like good people so I will take any help you can give.

1. Since we found the two seperate alarm systems, each with disable functions, and the computer is showing readings like the car is not running - have you seen or heard of something like this where the trans is not given power due to an alarm? Could a fault in the ignition switch or any other thing you know of cause this weird deal of no gears and no computer reading, but yet the car starts?

2. We have seen several Tech bulletins listed for different CD4E units that mention "no forward gears" but I do not have the money to join "All-Data" or one of the companies that allow you to get a look at tech bulletins. Do you have any idea what the issue turned out to be that caused no forward? Weird thing is that once shifter moved past reverse into a forward gear you then find reverse is gone again - so just weird.

3. There is a sensor on side of trans right behind driver side front tire area (think it is speed sensor) that looked like it had a twisted strand of wire sticking out at the plug end that made no sense. The plug looks to be a two wire plug point, and the sensor a two wire sensor, but this harness had a chunk of twisted wire that looked to be a third wire, (ground, or some other function) but not sure. If this sensor can keep the trans from shifting at all this may be an issue. Any clue if this sensor can keep trans from going in any gear would be welcome.

4. I have seen and heard many people say you need to get dealer to "Re-flash" the computer if issues with it, or after changing it. But I changed the body one on my 01 Escape with a unit having exact same numbers and it worked just fine. Have had similar results with a Windstar and others that said the dealer flash was a mandatory thing. Is having the computer showing no output with my tester something that will keep trans from working? If flashed by dealer will it make computer read and tell trans what to do?

I will have to get this vehicle on my car hauler and bring it over an hour to nearest dealer to get the computer flashed and I am worried that is not the problem. Usually if computer not responding the car will not start. Have limited experience with the alarm and computer procedures that may be at play on this. I am desperate and hope someone that knows the computer function will know why this thing does not go in gear and why computer reads nothing when tested. Seems odd that car will run if computer is totally out of it. Please HELP!!!!! I know this is asking a lot but I have no money and don't really know any other trans experts or computer experts to even ask. I figure you guys and the many people you deal with have probably seen and heard of everything, so I am willing to get on my knees and beg for any help I can get.

Thanks very much for any help - Paul

 

Is this an MX6 or a 626? The MX is similar to the Probe, being the same body with a different greenhouse are. The computer is obviously working, but the connection where you are attaching your code reader may not be actually connected to the computer.
If this were a CD4E, I'd say get out the ATSG manual, and find out where to check the line pressure, stick a gauge on it, and determine if the pressure was being developed.
If you have no drive in any gear, and this transmission has a similar solenoid, there would be an EPC solenoid that regulates line pressure to soften shifts with low acceleration and stiffen them up when you press on the gas pedal. If it is on vacation, you may not have enough pressure to work.
Being ignorant, I do not know if there is any alarm system that de-activates the transmission. Those I have seen will deactivate the starter relay or motor. so the engine won't crank, or they will kill the ignition system so it may crank but will never start.
I'd say you don't have an alarm problem.
Put in the engine, vintage, model, and if it is the factory model or a CD4E, and I can check the liberry. Without knowing the year, or if it is a 626 or MX6, I can't check anything.
Try starting it in N, and then putting it in D while up in the air. If you get engagement and normal upshift, without revving the engine a lot, then the speed sensor is likely functional. You may be tripping some sort of circuit by putting it in R, then the other drive positions. Without more info, I cant do much more.
You could also check down further in the site in the driveline & transmission section.
tom

added: This seems like a good place to start on the net, with two links embedded in the last para:
626 Transmission Faq - 1993-2002 (2L) I4 - Mazda626 Forums

 

Hi Tom

I had wrote in my tale of misery that it is a 626 but forgot the year which is 2001. It is a CD4E and Mazda gives it the part number LA4A-EL but it is the same unit. From all we have seen it is the same from 98 to 02. The Contour and Escape use larger output drive chain and have some gear splines that are bigger and have 30 teeth vs 28 etc. but still pretty much an electronic shift Ford CD4E. One thing that I did try yesterday that has me worried with this being a "computer" type issue is that I happened to run my test equipment on my Explorer (because it also has remote start like this car did) and when key turned off and out of ignition of my truck the computer "real time data" screen stayed on with the tester but read all 0% and things like that. So I wonder if with remote start do they hook up the system to keep the computer always ready to run so when you hit the remote start it fires engine? Possible we have this car running like that but trans portion of computer is off. I know little about these alarm and remote start units or even if you can get the computer to be turned on just for engine and not trans. Just for the hell of it I did tell my computer to see the Mazda as a 2001 2.0 Escort and the screen came up showing idle speed and other readings in real time but if turned to proper car - 2001 626 - computer brings up the screen saying make sure the key is on. So really wonder about the computer being out of whack because a remote start / alarm was on this and when we pulled the unit out the computer is now turned off somewhat. It would read as an Escort but that may be because pins are different on that computer so machine could see something that when told it is this Mazda it would not register. This car is driving me nuts. My brother is so sick of it he wants to try and buy a stick version that is wrecked and change everything - wires - pedals and all. That is not worth it.

 

Check the cigar lighter fuse.

 

We had the best wiring diagram we could find and it showed exactly what you mentioned - the lighter fuse also feeding computer - but lighter and radio all had power. We pulled every fuse and cleaned & checked, we even swapped circuit breakers with good units we keep from donor cars we scrap. Everything seems OK on that. Only issues we are not sure of is what was done by others in regards to alarms / remote start, and did guy we bought this from (with supposedly just a bad tranny) do something stupid like put the wrong computer in thinking that was problem but not knowing you have to get the exact firmware numbered replacement. I am going to try calling Mazda dealers to see if they can tell me what computer was in it new by the VIN number but not sure how helpful they will be. I called several service departments and asked if they had seen an issue like this and they all said no - it is impossible for car to start if computer is dead. One question I wanted to ask of anyone out there - can anybody you know get a rundown of Tech bulletins from Ford. Have seen several that mention no forward gears in the CD4E but I have no way to read bulletins and unless you join All Data or one of the expensive services like them you can not read actual bulletins. No idea if these are helpful on this thing but you never know. Just seems very odd that motor starts right up but analyser reads computer off and trans only goes in reverse very slow for a few seconds and goes completly dead if moved into any forward gear. Not even sure if the moving in reverse is actually strong enough to move car because it is still on lift.

 

Well, duh. The genius put in an Escort computer! Or not. Like looking for hens teeth to find a similar vehicle to check the computer & software Rev installed.
By 2001, they all had to have OBD-II diagnostic ports, so the 'pinouts' there have to be the same. If it works to read as an Escort, it should work to read as a Mazda.
I have not looked at the wiring schematic, but most have a KAM and 'power' feed. The Keep Alive Memory is fed 24x7, while the power is ignition key switch operated. IOW, they don't power the computer fully all the time, just the portion that has volatile memory content.
I went to carparts.com and searched for a 2001 mazda 626 'computer box' for an at/4 cyl and it came back with a page showing 11 4cylinder/at variants, over 30 different counting 6 cyl and mt models. Ugh... If you have a factory 'immobiliser', you may want to re-connect it... If it has one, I think it would be mounted under the center console stack towards the firewall, but that is for previous years Probe / MX6 models.
They also list 'transmission computer' as a valid search term, but they seem to be for extra features rather than the transmission, but what do I know... You can use carpart to determine the valid base unit, but the 'features' may be a little different spec.
Went to the library... Hmm, I don't think the wiring was done by FoMoCo. The feed for the cigar lighter is tapped from the ignition, but the feed for the radio taps there too, and the CPU gets fed from that{radio fuse} per the PDF I got. There are several computers on the schematics, so I'll punt, and offer to send the PDF files to you via email if you want.
tom

 

Called a half dozen dealers and at number six found a young guy that did not just tell me I would need to bring car in and have a tech look at it to get any information (at $175 an hour rates). He looked up what computer the car had installed from factory and it was the FS1881-A. The car had the unit listed except it was a -C in it when we purchased - so that is what I just recently purchased and put back in, a -C. He said that any unit with the same number, with a dash from -A to -E will work so I hope he is right, but since car had -A as new it may be someone did put this -C in the thing. He also said it does not have a seperate trans control unit for that year - most other Mazda's have it but this one does not - but it does show in his system a "CPU" under the fuse block. I think this may be a simple "body" computer that works with the main computer for windows etc. but may need to find out more. He also agrees that it is strange how telling the analyser it is looking at a 2001 Escort brings up data points (even if they are not all correct) but calling it a 2001 626 has the analyser tell you to make sure key is turned on. This is what you get when you put half a Ford in a Mazda I guess. I can get the analyser to see things in basic OBD mode but none of the options under that mode show trans control tests like I could see if working in the PCM test mode. What a strange set of issues this has become. Still not sure if computer can be running engine but have trans control turned off.

 

Have you checked the wiring harness between the PCM and the transmission? The EPC, if not enabled, would leave your line pressure low, and prevent good engagement. I would take a look at that given the trans had been gone through. In other words, check line pressure. You may be seeing 'engagement', but it is actually more residual friction. Unless you think it is actually engaging in R, with the normal feeling. Have you tried starting in N and then shifting back and forth between N and R to see if *that* is repeatable w/o making the trans inoperative?
tom

 

Why check that?

 

ibtim ... he's spamming for some sites and has posted the same response {almost} on other links.. I sent a note to "someone" in charge...
tom

 

Get it figured out yet? I'm currently dealing with the exact same problem on my neighbors 1999 mazda 626, same tranny, has no line pressure = no gears. I'll be wading through this one trying to track down the cause over the weekend, so if I find anything that might help you out I'll let you know. I assumed it was the pump at first but considering how the line pressure can be effected by electronic controls, thought I'd go through that system first. Transmission was rebuilt with a few upgraded parts 40k miles ago so pump failure seems unlikely. The sensors look like they were not replaced so I'll start testing there.

Good luck.

 

If you haven't figured this out yet, the problem on the one I was working on turned out to be where the shaft goes into the pump. It was cracked and would sometimes spin the pump but most of the time would not. So I replaced the pump. It is a weak part of the pump but I think the problem came from the kid shifting into drive before it came out of reverse. Not a good idea.

Just thought I'd mention it in case you haven't thought of that one so far.