Reading Codes...

7 posts in this topic

Hi to all! Thanks for this great site, it helped me a lot in dealing with O/D lights etc., in my 94, 4 L, ATX, 626.

I'd like to supply some information that might be of some help to owners of a 626 model similar to mine. Some, because I have really no idea how applicable this information is beyond a "1994, 4L, ATX 626"

I have noticed, and experienced, the confusion surrounding the reading of error codes. According to local wisdom, OBD-1 diagnostics was available until 1996, OBD-2 for models 1996 and later. However for 94 and 95 models Ford EEC-IV diagnostics was possibly used.

If you go to the Bradbury site (see pinned, V6 technical forum), it states to use the "diagnostic connector" and connect TEN (pin C) with GND (pin E), after which the "Check Engine Light" should give the error codes. However, in my 94, 626 4L model, only pins FSC, TSC, TAB and FAB are connected (in addition to the GND, +B), so that is not much use. Of course, the Bradbury site could be wrong, or I could be looking at the connector for the wrong model, except that the 626 Haynes manual (page 6-3, MAZDA 626 & MX-6, Ford Probe 1993 thru 1998) gives exactly the same story: connect STI (TEN in Bradbury) to the GND, and watch the CEL....

If you have EEC-IV you will be missing certain pins from your diagnostic connector. This is true of some 94 & 95 Mazda 626's and MX-6's.


Yet another version is available under the pinned messages in the 2.0 L 626 forum. According to this message for owners of a 1995 626, one should ignore the "diagnostic connector" and instead look for a trapezoid connector plus single female spade connector.


Connecting this spade connector (Self-Test Input) to the battery minus should give the error codes on the CEL. I tried this with my 1994 626, but no error codes what-so-ever. Again, this could be a mistake on my side, but the Haynes manual suggests the following: Connect a short jumper wire to the Self-Test Input (STI) and the Self-Test Ground (GND) terminals of the connector, and the CEL should give the codes. However, the indicated ground connector in the Haynes manual is absent in the trapezoid connector.

At Walmart they sell an Innova Equus "Ford Code Reader" #3143 (NO LCD) and #3145 (LCD) for around CAN$ 35, and it nicely supplies the error codes.


In case this is too expensive, check out the following website: http://dalidesign.com/hbook/eectest.html

This website (which is more informative and complete compared to the Code Reader booklet), and the Innova Code Reader give a lot of information on the EEC-IV diagnostics, like:

1) How to reset the ECU/erase codes without loss of the "learned settings": tried this and it works for my 94 626... This is useful, because one does not have to disconnect battery terminals etc.

2) How to do a cylinder balance test: tried this and it works for my 94 626...

3) How to do a Relay and Solenoid test: tried this, seems to work (the O/D light also comes on :rolleyes: ).

4) How to do a wiggle test: tried this by disconnecting the MAF sensor, without any response what-so-ever. So this one is questionable.

5) How to do a "Key On Engine Off" and "Key On Engine Running" test: tried this and it seems to work.


1) the explanation of two digit codes given in the Ford Code Reader manual and the dalidesign website are completely different from the MAZDA two digit codes. (Un?)fortunately my car didn't have any two digit codes, so I am not able to write anything about that. The three digit codes for the Ford and Mazda seem/are similar, if you compare the Haynes manual codes and the dalidesign/Innova codes.

2) Some three digit codes can appear that are not mentioned in any of the manuals/websites, like for instance 653 (KEOR), 675 (Memory Code). Any suggestions from Forum members on the meaning of these?

I hope this will clear up some (Not all. Why, for instance, does the Haynes manual state that a test light is to be connected between the STO terminal and the battery ground, while the dalidesign website states one has to connect the light to the positive terminal.......) of the confusion. I will write this up in a more DIY fashion, after inducing some two digit codes in the car and finding a more complete error code list for a 94 626. Any suggestions from forum members on the last point? Are OBD-I codes directly compatible with MAZDA(!) EEC-IV diagnostics for the 94-95 period?

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Thanks for the input. Looks like you spent a lot of time writing that up. I have seen the code reader you are speaking of and always wondered if that would work on the earlier models. Guess you confirmed it for the 94 B)

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At Walmart they sell an Innova Equus "Ford Code Reader" #3143 for around CAN$ 35

do you know where I can buy this online??


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Here's one but I have no idea how reputable the company is. Make sure you have exhausted all the ways listed to pull your codes before buying one of these. Generally for the cost of a paperclip you can do it yourself.

Innova Equus code reader model 3143

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dre2001 listen to jpit: he is right...

I could not resist :smile: opening this Innova unit, and there is nothing in it from an electronics point of view (LED, HEF4001, which is a CMOS 4001 (NOR gate, sorry for the jargon), a buzzer and two switches). However, it does prevent one from messing around with separate wires (you just plug it in), you have an audio output, which is handy while sitting in the car, and it comes with a nice code booklet (of which the two digit codes are useless). And it helped me double checking some of the "connector information" that is out there.

Based on what I now know, I would suggest checking the dalidesign website first. Next I would rig up something like an extension cord to have that LED/light & switch in the car while doing the tests: no need for audio in that way! Will post something on that in due time. And please post any trouble getting these codes: that helps everyone in finding all the different MAZDA modifications...

Regarding the codes jpit; is the shopmanual up to date on that? Is getting a subscription with Alldata a cheaper alternative compared to buying the shopmanual? Oh, before I forget, check out the Alldata website; it has repair instructions on the Mazda 626 for free....

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B) thanx guys, but i have a BIG problem, mine does not have a CEL :ohmy: -_- , and I really need to know if it has codes or not and have anything wrong with it fixed. I only have an ABS light. :angry:

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Yep, I know - have same model (94, 2L...not 4 :rolleyes: as stated in my mail, 626 ATX) Let us know about your "code reading" progress: didn't get a reply on my question if EEC-IV codes and OBD-1 codes are the same, so any information on two digit codes you have is welcome!

Regarding the format of the codes: they are all repeated, like this (F is very fast code, 111 is slow code, P is separator pulse, and 675 are fast, memory stored codes.)

KOEO test: F - 111 - 111 - P - 675 - 675

after clearing: F - 111 - 111 - P - 111 - 111

KOER test: 2 - F - 536 -521 - 653 - 536 - 521 -653

in this case you forgot to turn your steering wheel and press the brake after the engine ID (2). If you do that, you get:

KOER test: 2 - F - 653 - 653

More later.

(that is, you got rid of the errors 536 and 521)

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