2002 P5 will not start. Please Help

D

dirizarr

Member
:
2002 Mazda Protege5
A huge mistake was made when putting a new battery and the battery terminals were crossed and the main fuse / ECU fuse burned. Got a new 100 amp fused corrected the battery terminal mistake and the car fires up but wont start or stay on.

So the car will crank i checked the plugs im getting no spark. I believe the problem is coming from a sensor or something electric because the car has been off for days now and the heat gauge is pinned at HOT when ignition switch is on.

I got another ecu/pcm for a 2002 protege5 automatic and the car still will not start thinking I might of burned the ecu.
Another has any ideas? Car had no issues until I changed the battery and made that embarrassong mistake woth the batter terminals.
 
Sounds like a fried ECU.

I don't know about Mazda, but even the aftermarket AEM ECUs do not have reverse polarity protection. I have heard of an AEM EMS-4 blowing at the touch of reverse polarity. When opened, the magic smoke came out and a few traces were blown.

I don't think you can just swap another ECU... You need to get it re-flashed for your specific car at the stealership.
 
Well I got a ecu with the exact numbers to match. I hope what you are saying is not true or I am looking at serious money :-(
Also my ecu does not smell burned.
The ecu I swapped in is the identical numbers from a running protege. Still won't fire up plus the snap on scanner reads link error. :-/
 
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dirizarr said:
Well I got a ecu with the exact numbers to match. I hope what you are saying is not true or I am looking at serious money :-(
Also my ecu does not smell burned.
The ecu I swapped in is the identical numbers from a running protege. Still won't fire up plus the snap on scanner reads sync error. :-/
Click to expand...

You won't smell or see anything until you open the ECU.

There may be other things that went wrong when reversing the polarity of the battery, however considering that you do not have a spark output tells me that the ECU simply is not responding when it is given the command OR it cannot pick up a timing signal from the sensors. Either way, its internal to the ECU.

To elaborate on what I experienced. I wired up a race car for my team and it was running up to temps, albeit with tuning required. I used an AEM EMS-4, then I left for a nearly a week on holidays and the other guys put on the battery backwards. After that happened, the car was dead silent, no spark, no fuel... nothing.

Furthermore, I do not know how it is on Mazdas, but on Dodge Caravans, If you do not re-flash an ECU (PCM) to the specific vin number and milage of the car, then the car will not run. I am only saying this because I have not experienced swapping ECUs on any Mazda before, I do believe it is the same (or similar) procedure. I believe part of the reason is possible variations in sensors and whatnot that the car may come equipped with. I heard that some old 80's Chryslers had something like 15 different versions of a wiring harness for the same model year!

Besides, I don't think a Dealership will charge you hundreds to re-flash the ECU.

I would wait on another person to chime in before taking my advice as I am talking from my own experience.
 
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OK so with the ecu unplugged....the temp gauge shoots up to hot with ignition switch on. I unplug the temp sensor and the gauge still rises to hot. Weird!
 
^ I hate to say this, but you might have fried other electronics in your car. I would wait for someone more experienced to answer this though, or search around on google.
 
I did a bit of google searching, and someone from clubprotege did the same thing as you, but they never cranked the engine. Replaced the blow fuses (main fuse, ours is 100A) and it all works fine now.

The other thing I read is that the starter motor could spin backwards in reverse polarity, and I can believe this. This means that there is no tension on the timing belt and your timing is probably off, but I doubt this is the issue since you are telling me there is NO spark at all.
 
Thanks big dill...Yes I replaced the main fuse because it blew. Question is why would the temp gauge go to hot once switch is on with the ecu unplugged? That's weird.
I might have to start a post about if ecu cannot be swapped on our cars....instead need to be reflashed.
 
I don't want to lead you in the wrong direction, but you may have other electronics on the car that went bad.

A re-flash at the dealers with a new ECU might run you $150, but I do not know if it will fix the gauge problem.
 
I agree I think it is something else as well I have to look into. Still wonder if a swap of ecu work.
 
The ecu does not need to be reprogrammed when swapped. People swap them all the time.

Check over all fuses. And check all wires to make sure they're not burned. Sounds like it could have melted a wire somewhere and it's grounding out on something
 
Tweety...so our mazda computers do not need reflashing?
OK because I put one from another p5 same numbers to match and car didn't fire up.
Plus the temp gauge moving up to hot with ecu off raises a flag that it might be within the harness?

tweety2300 said:
The ecu does not need to be reprogrammed when swapped. People swap them all the time.

Check over all fuses. And check all wires to make sure they're not burned. Sounds like it could have melted a wire somewhere and it's grounding out on something
Click to expand...
 
I only got to check to fuses to on the engine bay and the ones under the drive side dash. Not sure of any other.
 
Big Gill...found the 10 amp fuse under the dash and it was burnt. Replaced and problem fixed. I do have a check engine light on but I'll worry about that later.
Just glad to hear the car on.
Just want to thank everyone for their help. I am greatly appreciative. :)
 
dirizarr said:
Big Gill...found the 10 amp fuse under the dash and it was burnt. Replaced and problem fixed. I do have a check engine light on but I'll worry about that later.
Just glad to hear the car on.
Just want to thank everyone for their help. I am greatly appreciative. :)
Click to expand...

Nice to hear the bigger problem is fixed. Whats the engine light code?
 
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