Used ECU Replacement

[ParkerV2]

Long story short my car has been down for a couple of months with a fuel issue.
Accessport was registering 0 Voltage on the high pressure pump and the psi wont go above 1,000.

Things i have replaced,

-Relief Valve
-Fuel Pressure sensor
- In tank Fuel Pump
-High pressure fuel pump AND internals
- Found two small vacuum leaks and fixed those
-New battery

Ive taken it to multiple shops and they all told me to replace the entire fuel rail just so i could replace that sensor which ive already done.

A guy local to me who co owns a mazdaspeed specialist shop finally got to look at my car and after thoroughly looking at it he told me i need to replace my pcm.

My question is, what do i need for mazda to be able to reprogram a used ecu?
Same year? Same gen? matching ecu codes? immobilizer? Keys?
ive seen different answers on this so i wanted to see if someone could clarify before i waste even more money.
Thanks in advance for your help

[Molsen_miata]

Im having the same issue let me guess p0300 code and cant give more then 20% throttle or go into boost? basically car has gone into limp mode?

[ParkerV2]

Originally Posted by Molsen_miata Im having the same issue let me guess p0300 code and cant give more then 20% throttle or go into boost? basically car has gone into limp mode?

Yup! Idles decent but AFR's are rich, in the 13's. Wont boost or anything, been dealing with it for 2 months it sucks

[5doorsoffury]

The immobilizer system is built into the cluster so im not sure if the pcm replacment has anything to do with that. I believe you can replace the pcm and flash it with an ap or versatune but i am not sure. I would imagine if you show up to the dealer with the title and cash as well as some lube of your choosing they can get it done.

[ParkerV2]

Originally Posted by 5doorsoffury The immobilizer system is built into the cluster so im not sure if the pcm replacment has anything to do with that. I believe you can replace the pcm and flash it with an ap or versatune but i am not sure. I would imagine if you show up to the dealer with the title and cash as well as some lube of your choosing they can get it done.

Ok i will try that thanks for the suggestion, i was told i cant flash from the AP because ill get a vin mismatch error code and wont run. Ill see what the dealer can do, only problem is title isnt in my name but ill see

[5doorsoffury]

if you bought a gen 2 ap it can only do a gen 2 ecu and same for gen 1 and speed 6. The used ecu needs to be of the same generation. Its been a while since i married a ap but i dont remember anything about entering vin info.if you get a tech package ecu and you dont have a tech package and vice versa it wont work. Im not a expert in ecu swaps. I would do recerch there have been a few threads where ecus have been replaced.

[ChuckNorris90]

Originally Posted by ParkerV2 Long story short my car has been down for a couple of months with a fuel issue. Accessport was registering 0 Voltage on the high pressure pump and the psi wont go above 1,000. Things i have replaced, -Relief Valve -Fuel Pressure sensor - In tank Fuel Pump -High pressure fuel pump AND internals - Found two small vacuum leaks and fixed those -New battery Ive taken it to multiple shops and they all told me to replace the entire fuel rail just so i could replace that sensor which ive already done. A guy local to me who co owns a mazdaspeed specialist shop finally got to look at my car and after thoroughly looking at it he told me i need to replace my pcm. My question is, what do i need for mazda to be able to reprogram a used ecu? Same year? Same gen? matching ecu codes? immobilizer? Keys? ive seen different answers on this so i wanted to see if someone could clarify before i waste even more money. Thanks in advance for your help

Hello everyone!

What you need mate is to get an ECU with the exact code. Each ECU usually has two codes. One is from the car manufacturer and the other from the manufacturer of the ECU. If you get one unit that matches one of those 2 codes it will do the work. Those codes are usually found in the label of the unit itself.

Knowing this you can do two things:

1- Buy a used unit and flash it by yourself or in any near specialized workshop. For this purpose, eBay might do the trick.

2-Or you can buy it inmo off. I really don't know if you can get that unit with the immobilizer system canceled, but I guess it pays off the search.
Here you can find inmo off units.

I'm no expert on the matter, just a Mazda user with a lot of experience and failures behind my back... but if you want to ask me anything, I'd be a pleasure to help you out.

[ParkerV2]

Originally Posted by ChuckNorris90 Hello everyone! What you need mate is to get an ECU with the exact code. Each ECU usually has two codes. One is from the car manufacturer and the other from the manufacturer of the ECU. If you get one unit that matches one of those 2 codes it will do the work. Those codes are usually found in the label of the unit itself. Knowing this you can do two things: 1- Buy a used unit and flash it by yourself or in any near specialized workshop. For this purpose, eBay might do the trick. 2-Or you can buy it inmo off. I really don't know if you can get that unit with the immobilizer system canceled, but I guess it pays off the search. Here you can find inmo off units. I'm no expert on the matter, just a Mazda user with a lot of experience and failures behind my back... but if you want to ask me anything, I'd be a pleasure to help you out.

Thanks for your reply. So you're saying I have the option to either buy a used one off ebay with the code matching my ecu code, or I can buy one off of that website and they will program it? i went to that site you linked and didnt see one for a mazdaspeed or mazda 3. Only saw mazda 6, mazda mx3, or mazda 5.

[ChuckNorris90]

Not exactly, an inmo off unit in Ebay it's hard to find, and the guys for the second site, I don't believe they program anything, they just send you the ECU inmo off, which it's almost the same thing. In any case, you should consider too, the option of getting the same code ecu and then flash it in a near workshop. That's what eBay it's best for. Also, don't you have any scrap yard near, where you can search your ECU?

[ParkerV2]

Originally Posted by ChuckNorris90 Not exactly, an inmo off unit in Ebay it's hard to find, and the guys for the second site, I don't believe they program anything, they just send you the ECU inmo off, which it's almost the same thing. In any case, you should consider too, the option of getting the same code ecu and then flash it in a near workshop. That's what eBay it's best for. Also, don't you have any scrap yard near, where you can search your ECU?

I found one on ebay with the same code as mine except the very last letter is B and mines C. This should be perfect right? He says it came off a running car but its pretty cheap compared to others, might just take the gamble and order it

[ChuckNorris90]

Originally Posted by ParkerV2 I found one on ebay with the same code as mine except the very last letter is B and mines C. This should be perfect right? He says it came off a running car but its pretty cheap compared to others, might just take the gamble and order it

I wouldn't take the risk... As far as I know, it has to be a perfect match.