1996 Mazda 626 V6 automatic

Hi champs, my car stopped suddenly while driving. And then it was towed to workshop and spend money $470 so far. But no luck. So I decided to repair my self with help of YouTube.
Issue is no spark and no fuel injection pluse. No engine light in dashboard. Car cranks. I doubt ecm is not working due to short circuit somewhere (I assume).
My findings: when I check for the red lines on my attachments, I found it is shorted to ground. Don’t know how to find shorted location.

Could you experts please help me to identify issue.

Ok, First of all, why do you think you have a short to ground? Do you have a blown fuse? If you do have a short to ground, the best way that I have found to find it is to do a resistance test from the red/black wire and frame. If you read continuity, then I would unplug all of the affected components (o2, fuel injectors, etc.) one at a time and see if it goes away. A shortcut may be to start at the Main relay and see if you can separate the red/black wire and the red/white wire. If you can, do you still read a short on the red/white wire? red/black wire? Then go from there.

Thanks Dave. Appreciate your reply. No blown fuses. But I found red/black wire shorted to ground. As per danner’s YouTube video, I am unplug sensors one by one. Few sensors like left,right,middle heated oz sensor and Vris sensors difficult to locate. I am in that process of doing that. I will also seperate that two wire in relay to narrow down. I will share my findings soon. Meantime my doubt is will short circuit shut the ecm? Thanks mate

If I understood you correctly, Your wondering will a short to ground fry your PCM? Anything is possible, but on this circuit I would think you would have had a blown fuse before that happened. If your asking if this short to ground will shut the car down the answer is yes. It looks like that wire is one of the main feeds to your injectors, fuel pump, etc. Post what you find step by step if you can. Or if your having any trouble, reach out and maybe one of use can help. Good Luck

Hi Dave101,

I have disconnected sensors one by one while checking red/blk short to ground. As per attachment, I disconnected all sensors on bottom of my attachment. But note 2 oz sensor can’t disconnect. Note 1 oz sensor disconnected. And two other (note 3&4) can’t find. Wondering if these sensors really exists in my car.

On my second attachment, the blue lines and from connector B to ecm, red/blk line is good. But from connect A to all other yellow line is shorted to ground. Only one oz sensor outstanding to disconnect.

Pls give me direction how to proceed further from here. I will be flying out tmrw and will be back to home after 21 days. So I may not able to do any check. Just for your information.

Thanks a lot

Additional, on fuse box, 60A BTN fuse is short to ground and other two blade fuses too. Please see attached pics

What is BTN FUSE for.

Is this a 626 DX, ES, or LX ?

60 Amp (Yellow) Taillights, Foglights, Stoplights, Courtesy & Hazard Lights, Power Door Locks, Power Seats

Attached is the power distribution diagram for BTN fuse 60A.

I don't understand how you have a short to ground on there and NOT have a blown fuse.

JustJuan wrote: Is this a 626 DX, ES, or LX ?

60 Amp (Yellow) Taillights, Foglights, Stoplights, Courtesy & Hazard Lights, Power Door Locks, Power Seats

Attached is the power distribution diagram for BTN fuse 60A.

I don't understand how you have a short to ground on there and NOT have a blown fuse.

That was my initial though as well, however I have seen shorts to grounds on other cars that didn't blow the fuse. But in those cases there was an aftermarket add on attached to the circuit. I haven't asked but is there any aftermarket add on's to this car,? (alarm, gauges, etc.)

Asfaruk,
I understand you have no spark and no fuel. What checks have you done to determine a short to ground? Did you isolate the entire circuit before you checked for ground? What other checks have you done that led you down this road?

Asfaruk,
I understand you have no spark and no fuel. What checks have you done to determine a short to ground? Did you isolate the entire circuit before you checked for ground? What other checks have you done that led you down this road?

www.scannerdanner.com/scannerdanner-prem...se-study-part-1.html
This is a good video that seems to relate to your problem. Just pay attention to what your doing and don't shock yourself like Danner did!!!:blink: :ohmy:

Thanks for your reply mate. Its is Mazda 626 V6 2.5L Eclipse

I have completely removed car battery and disconnect the wiring harness of ECM.

Yes. Immobilizer installed on this car. but i deactivated 1 year ago by turning off. But i did not remove it from car. i believe immobilizer system was installed by mazda showroom.

There is no problem for more than 1 year after being disconnected the immobilizer.

Kindly see attachment

Gents, Sorry for late reply. I am in FIFO work now. So i cant do further check until i back home which will be on 04/07/2018.

Really appreciated for your reply... Thanks mates

I/P means instrument panel. The joint box is located left side of it. See pic.

I would start pulling those five fuses in the joint box that are connected to that WHT/RED wire and see if the short goes away.

I tried it already. But I did not know that one is called as I/P. I traced backwards that WHT/RED wire (It is actually thicker wire than any other wire used in there) and it gone into I/P and I unplugged it and short gone at main fuse box. But when I checked the terminal in IP that connects to WHT/RED wire, it shorted there itself.
Question is:
1) my car battery used to drain completely if I don’t drive car for a day. May this (BTN short) issue be the reason for it?
2) Could BTN short issue shut ECM? In other words, is it linked with NO SPARK/NO FUEL INJ PLUSE issue?
3) Since ground shorted on IP itself, How can I proceed further step/action?
4) Could you please share your book with me? My email id is asfaruk@gmail.com

Attachment:
Car’s Name plate
Immobilizer picture
ECM port Picture
ECM Harness picture.

Asfaruk wrote: I tried it already. But I did not know that one is called as I/P. I traced backwards that WHT/RED wire (It is actually thicker wire than any other wire used in there) and it gone into I/P and I unplugged it and short gone at main fuse box. But when I checked the terminal in IP that connects to WHT/RED wire, it shorted there itself.
Question is:
1) my car battery used to drain completely if I don’t drive car for a day. May this (BTN short) issue be the reason for it?
2) Could BTN short issue shut ECM? In other words, is it linked with NO SPARK/NO FUEL INJ PLUSE issue?
3) Since ground shorted on IP itself, How can I proceed further step/action?
4) Could you please share your book with me? My email id is asfaruk@gmail.com

Attachment:
Car’s Name plate
Immobilizer picture
ECM port Picture
ECM Harness picture.


The answer to the first two questions is Yes. This could be related to both of your issues. Looks like this one could be a mess and take a while. The first thing I would want you to do is lets try to isolate some of this and do some checks. In the main fuse panel, there is a 15a fuse called Tail fuse in your diagram. Can you pull this fuse then check to see what the status of your short is? This I believe will take out most of the outside lighting.