I've had to get my rx8 towed to mazda because it wouldn't start.

Mazda are now telling me that the ECU needs replacing and have quote me about £1500 for the repairs.

The part codes they have given me are:

MN3Z 18 888 1F (ECU)

and two bolts:

M9YA280501
M9YA280601

I asked them if I could give them second hand parts to use and they said this was ok.

So now I am looking on Ebay and the closest match I can find for the ECU are these part codes:

N3H8 18881 F
N3H8 18881 G
N3H8 18881 L

My question is, will any of these parts be compatible with my car?

I cannot find a reference to MN3Z 18 888 1F anywhere on the internet?

Also, they have quoted me over £100 for the 2 bolts!!!!!

I also cannot find any reference to the part codes they have given me for the bolts on the internet.

My car is currently at the Mazda garage so I would really appreciate any quick responses.

Thankyou

 

I'm sorry, can't help with that, ECUs are rarely replaced. Just out of curiosity, what are the symptoms? It's very very unusual for an ECU to fail.

 

I can't get the car to start. It cranks but the engine doesn't turnover.

I called breakdown guys out and they tried deflood technique, which didn't work.

Got a local mechanic to try a tow start, which didn't work.

No local garages wanted to know so I got it towed to Mazda who reckon its not starting because the ECU needs replacing.

Am I being ripped off?

Shall I get it towed back to my house and find some sort of car electrician?

 

Did anything happen to the electrical system that could have shorted out the ECU?

Have they actually checked to see if there is spark and fuel?

The room fuse in the cabin can result in the ECU OBD2 port not getting any power...you wont be able to connect the scan tools...and they might think that the ECU is fried

I wouldn't let them replace it until they know for sure that is the problem

As for the bolts...your UK cars have special non-tamper ECU bolts. I'm sure a standard M6 bolt like the rest of the world uses would work ;-)

Is the car a MT or AT?

 

I don't know about rip-off, but it's a hell of a jump from "it doesn't fire" to "here's a $3000 bill for something that might work" :P
I'd dig deeper, try simpler things first...
- proper deflood
- compression test
- fuel pump test
- ignition coils

 

That is the dealer way, diagnosis by parts replacement.

 

Cranking IS turning over. Both terms refer to the rotation of the engine, neither refers to combustion.

So is it cranking but not firing? or is it not even cranking? Two entirely different issues with different possible causes.

Not even getting pull started suggests that this is a ground, spark, fuel, or e-shaft sensor problem. An ECU failure is still certainly possible too, but you need to rule out the cheap stuff first.

The only 2 ways that I have seen an ECU damaged over the years on this forum is an alternator failure and resulting overvoltage, or connecting the battery cables backwards and flowing electrical current backwards through the car. If you are positive that neither of those occurred, then keep digging for other options.

 

Mazda have said if I provide a used replacement ECU they will try and fit it. Managed to get one on ebay for £23 so what the hell! If it works they will only charge me for the reprogramming and diamond plated bolts.

Obviously I'm pretty doubtful it will work though. I'll probably just have to pay up for the work so far and get her towed home.

Pretty sad story, I bought her in March this year for £1900. Shes a 2004, 192, MT and I've done about 5.5k miles in her. I've honestly loved every minute of having this car. Only things I've had done is a new clutch put in and new brake pads for its recent MOT.

Now all of a sudden it wont start, completely out of the blue, no previous starting issues for me whatsoever. I was skeptical about it being flooded tbh because I hadn't stopped the car cold, I've always been dead careful with the standard maintenance. I just came home from work one night, my standard commute driving like a F1 driver! Then I go to start her in the morning and get nothing, just cranks.

My only theory at the minute is that the wankel hating breakdown guy fried my ECU when he tried to deflood the car. And this new ECU issue is blocking the Mazda guys from the real underlying issue that's causing it to not start. My faith in Mazda is virtually non existent at the minute.

I will find out exactly what work they have carried out tomorrow and I'm guessing she'll be back chilling on my drive on friday.

God knows where I will take her next!

 

That sounds like fuel pump sudden death. Not unheard of. Just saying. Or.. you know... something silly like a fuse. Sorry, I have about as much faith in random techs -- Mazda or otherwise -- as you.

You don't just fry an ECU by cranking the car, unless it has gone for a swim or something.

 

The reason I think the breakdown guy may have fried the ECU...

Before he arrived when I tried to crank the car did nothing it just wouldn't start.

Then after he arrived and had hooked my engine up to his with jump leads. When we tried to deflood the rev counter started going up and down like crazy. He didn't seem too worried about this and thought it was pretty normal. When mazda told me that the ECU needed replacing they used this rev counter thing as a symptom of ECU failure. They said the car actually thinks its going 7mph and that's why it wont start. Is this rev counter issue a clear sign that the ECU has failed because I can't find any info on this?

The only other electrical engine related thing that has happened is a couple months ago a warning light came on the dashboard. Its a red car with a key inside it and it is blinking on and off. When I googled it I thought it was to do with keyless entry and my car doesn't even have this, so I chose to ignore it. Could the fact that this warning light is being shown incorrectly be a symptom of ECU failure?

 

Um, yeah, if the tach was going nuts when he hooked up the jump leads, he probably hooked them up backwards.

 

So, is my only option to get mazda to fit a new ECU?

Or, can this be done by any car electrician?

I have bought a used replacement ECU on ebay.

Or, should I just sell the car for scrap?

 

Replacement ECU is going to be the only option for repair, if indeed the ECU is fried. It's hard to give a precise diagnosis on it because it is hard for us to really have all the tiny facts that make a big difference.

No, don't worry about an electrician. You wouldn't call one to try to rebuild circuits on your computer's motherboard, so they wouldn't solve anything if the ECU is fried. It's basically the same concept there.

 

If the breakdown guy did fry the ECU and lets say I do get mazda to replace it. Surely this will bring me back to the original issue as to why it wouldn't start. Assuming that the ECU wasn't friend before he hooked up the jump leads?

I'm so confused right about now with the whole thing!

Thanks for your responses though guys!

 

There are many reasons for not starting. It could have been flooded, in which case something else on the car failed, like the starter, battery, ignition coils, plug wires, spark plugs, grounding points, e-shaft sensor, etc...

Not enough information yet to be able to point you in a specific direction.

 

I'm waiting for the mazda guys to ring me back and I've got a few questions to ask so hopefully that should provide more information. I thought mazda would have surely checked all those things as standard???

This is what i was going to ask:

1) what is the current cost of the repair work?
2) have they checked that all fuses are ok?
3) have they checked that the spark plugs and ignition coils are ok?
4) did they try and do a proper deflood?
5) have they done a compression test?
6) have they done a fuel pump test?
7) is the actual engine in good working condition?
8) have they tried resetting the ECU?
9) how have they decided that the problem is because the ECU has failed?
10) is it because the rev counter is bouncing up and down, or have they actually tested it?
11) have they already removed the ECU from the car?
12) will you have to damage the ECU bolts to test the used one I was going to provide?

Anything else I should ask, or are any of these questions too dumb to ask lol?

 

Mazda only "checks stuff" by replacing it. There are some exceptions, but assuming that Mazda checked every part of the car that could possibly affect a problem is a very bad assumption.

It's the reason that we get nervous when a new owner says that the car was maintained "religiously by the dealer", because all that means is oil changes, everything else is ignored and never checked. The owner gets lulled into a sense that the dealer is doing more than oil changes and absorbing the cost of full inspections on other items without passing the cost on to the owner. That simply doesn't happen.


The questions look fine, definitely force them to give you clear answers. The more vague they are and the less responsive they are, the more you have to worry about that they are just throwing your money at the car hoping it works.

 

Hey guys just thought I'd post a conclusion to this bizarre ECU issue in case someone might find it useful in the future!

Ok, so it turns out the ECU was the issue indeed!

I found a used ECU on ebay for £60 and took this to mazda who said they would have a go at fitting it for me.

Then they took about a week before calling me to say that everything is now fine and the car is fully up and running!!

They charged me £230 for the labour and they used standard bolts to fit it at no extra charge!

They even give the car a full clean inside and out!

So, my faith in Mazda has been momentarily restored I guess.

However.......

I literally drove the car out of the mazda dealer and the CEL came on. I rang mazda straight away and the service rep there said she will give me a call back - but they never did.

I decided to just drive it round a bit and see if there were any obvious issues but to be fair the car seems absolutely fine and iv done about 70 miles but the light is still on.

I'm gonna take it somewhere else soon to get the code read, but any ideas from you guys in the meantime?

Could some sort of sensors have been damaged during this ordeal?

My car was at the mazda dealers for 23 days LOL

Cheers

 

Anything is possible, best to scan the code. Could be anything from a loose gas cap to electrical gremlins to engine problems.

There is still the fact that the car stopped and appeared flooded, which is the reason you needed a boost in the first place. Wast he cause of that identified?

 

Nah, they didn't tell me what they thought had caused the ECU to fail they just told me that the ECU had failed.

I'm still going with the assumption that the breakdown guy killed the ECU when he tried to jump start it.

However, I've got the original ECU and it doesn't look fried or damaged in anyway - very weird.

I will hopefully get the code scanned sometime this week and post the results.

I also definitely need to get a compression test done (I know I should have got this done on the day I bought it, but the dealer promised me the compression was good).

For the time being though, I'm just enjoying having my baby back on the drive because I seriously thought she was a gonner!

 

if u can gimme the ECU and your VIN I can flash the ECU to match your car for a small fee, but u got that taken care of already.

ECU can be killed if the Voltage regulator fails.

check the CEL first to see what it is.

 

Oh and on the plus side the money I have saved on petrol paid for the repairs!!

 

I see no one picked up on you saying your immobilizer came on (that's the little red car with the key) it's not just for the keyless entry. Did this start blinking when the car was running or off? If you noticed it when the car was off that's normal. If it started blinking when the car was running as far as I know that's not normal. As for a 04 MT 193 I think the 193 is the HP of the engine and if it's a MT it's a 230 6 port you have.

 

He's a Brit... the low power cars have 4ports and 5speed MT

 

Was there any way for the Mazda dealership to check your original ECU to see if it failed without simply replacing it?
The factory would have to have some diagnostic equipment or self check routine that could identify faulty parts.