ECM swap

[bochuck]

I have recently had a lot of trouble with my car idling rough and generally misbehaving while driving. Possible harness issue. Having it looked at right now. The dealership rep initially told me it was an ECM issue. Today the service tech told me it was harness related. The new ECM retails for like $1500 according to the rep. Scared me enough that I bought a used one for $70 to reflash with my tune. Now that the problem is harness related and I have a "new" used ECM I was wondering something. If when I decide to take my car back to stock for a trade in can I just swap the stock ecm instead of getting the one in my car now stock tuned again?

[mondtster]

Just flash a stock cal to the ECU in the car. It will be done in less than 5 minutes.

 

Replacing the ECU can be a bit of a pain since you'd have to have the immobilizer programmed. Otherwise the car won't start.

[Thinking out side box]

unmarried AP's are pretty much worthless because of the cost for Cobb to wipe it clean. It's a theft deterrant. As Phate mentioned, just go to the dealer and ask them if you can unmarry the AP from the car, unless however it's tuned for parts that are on it, in which case, the new owner will want the custom tune and the AP so you should just leave it with the car.

[Thinking out side box]

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I have recently had a lot of trouble with my car idling rough and generally misbehaving while driving. Possible harness issue. Having it looked at right now. The dealership rep initially told me it was an ECM issue. Today the service tech told me it was harness related. The new ECM retails for like $1500 according to the rep. Scared me enough that I bought a used one for $70 to reflash with my tune. Now that the problem is harness related and I have a "new" used ECM I was wondering something. If when I decide to take my car back to stock for a trade in can I just swap the stock ecm instead of getting the one in my car now stock tuned again?

[scottmcphee]

I have recently had a lot of trouble with my car idling rough and generally misbehaving while driving. Possible harness issue. Having it looked at right now. The dealership rep initially told me it was an ECM issue. Today the service tech told me it was harness related. The new ECM retails for like $1500 according to the rep. Scared me enough that I bought a used one for $70 to reflash with my tune. Now that the problem is harness related and I have a "new" used ECM I was wondering something. If when I decide to take my car back to stock for a trade in can I just swap the stock ecm instead of getting the one in my car now stock tuned again?

 

I think I may be in a similar boat as you.

 

Were you getting OBD codes coming up and cutting cruise control..

 

What was the solution and $$ for the harness repair (more detail please)?

[Tuning Alliance]

I have recently had a lot of trouble with my car idling rough and generally misbehaving while driving. Possible harness issue. Having it looked at right now. The dealership rep initially told me it was an ECM issue. Today the service tech told me it was harness related. The new ECM retails for like $1500 according to the rep. Scared me enough that I bought a used one for $70 to reflash with my tune. Now that the problem is harness related and I have a "new" used ECM I was wondering something. If when I decide to take my car back to stock for a trade in can I just swap the stock ecm instead of getting the one in my car now stock tuned again?

 

Sounds like a dirty or bad maf to me.

 

-Brian

[bochuck]

So turns out it wasn't harness or ecu related. It's almost like the mechs at my local dealership do what I do (guess at the problem) and get paid for it. I replaced the camshaft sensor and the problem went away for the most part. Not trying anything new to fix it. Car is now 11/12 years old. It's almost like I just wait for the next thing to break and then throw money at it. Car runs decent enough right now. Just small things that most anyone else wouldn't notice.

[scottmcphee]

Just flash a stock cal to the ECU in the car. It will be done in less than 5 minutes.

 

Replacing the ECU can be a bit of a pain since you'd have to have the immobilizer programmed. Otherwise the car won't start.

 

I bought an identical part number ECU off ebay, and copied the rom from my existing ECU to the replacement using Tactrix 2.0 cable and ECUflash software.

 

Rom load went well, but car did not start on replacement ECU, as expected. code p1571 coming up - information mismatch... Needs key registration ceremony at dealer because of swapped equipment. So I booked an appointment.

 

THEN I learned of the single small 8pin EEPROM chip on the ECU that holds all the fingerprint data for the car ... unsoldered it from the original ECU and moved it over and soldered it onto the replacement ECU.

 

Car magically starts and runs fine. Successful complete cloning process.

 

No dealer visit required to register keys, cancelled the appointment.

 

Thanks to Tactrix support and RomRaider forum for pointing out the EEPROM chip to move.

[mondtster]

I bought an identical part number ECU off ebay, and copied the rom from my existing ECU to the replacement using Tactrix 2.0 cable and ECUflash software.

 

Rom load went well, but car did not start on replacement ECU, as expected. code p1571 coming up - information mismatch... Needs key registration ceremony at dealer because of swapped equipment. So I booked an appointment.

 

THEN I learned of the single small 8pin EEPROM chip on the ECU that holds all the fingerprint data for the car ... unsoldered it from the original ECU and moved it over and soldered it onto the replacement ECU.

 

Car magically starts and runs fine. Successful complete cloning process.

 

No dealer visit required to register keys, cancelled the appointment.

 

Thanks to Tactrix support and RomRaider forum for pointing out the EEPROM chip to move.

 

So you didn't believe me that the immobilizer needed programming?

 

Swapping the eeprom is another option of doing it, or reading what is on your original eeprom and programming it to another one. Any way you do it along these lines will require the removal and replacement of the eeprom. I have not been successful with reading or writing them while still installed on the circuit board.

 

While not hard, it is an inconvenience that can be avoided if the ECU really doesn't need to be replaced. In the OP's case, I see no reason to replace it just because the current ECU has been flashed with a performance file.

[scottmcphee]

Actually, it's not just the immobilizer needs to be reprogrammed.

 

The Body Integrity Unit BIU (where immobilizer function resides), the instrument cluster, and the ECU -- all three pieces --- have to get a key registration procedure done by dealer if you swap out any one of these parts. If you don't move the eeprom over on the ECU.

 

Registering keys involves: dealer using SSM tool on the diag port tells these 3 components to forget (erase) their image of all keys, then adds all keys (up to 4 maximum) to the 3 components again, so they match.

 

My dealer charges $75 plus tax to register set of keys with the car.

 

I saved $75 plus tax, by moving the eeprom over on the ECU.

[mondtster]

Actually, it's not just the immobilizer needs to be reprogrammed.

 

The Body Integrity Unit BIU (where immobilizer function resides), the instrument cluster, and the ECU -- all three pieces --- have to get a key registration procedure done by dealer if you swap out any one of these parts. If you don't move the eeprom over on the ECU.

 

Registering keys involves: dealer using SSM tool on the diag port tells these 3 components to forget (erase) their image of all keys, then adds all keys (up to 4 maximum) to the 3 components again, so they match.

 

My dealer charges $75 plus tax to register set of keys with the car.

 

I saved $75 plus tax, by moving the eeprom over on the ECU.

 

Call it what you want but it's the same difference in my book. The keys need to be programmed to the car when you switch the ECU, one way or the other.

 

That's why I wouldn't recommend swapping ECUs just because one has an aftermarket file in it. It's a whole lot easier and nearly painless to just flash a factory program back in the existing ECU. Five minutes, done.

[scottmcphee]

Good if your existing ECU is in good shape, and I agree a new software dump onto your existing ECU is always going to be easier to do, and the preferred route... if you've got a good ECU.

 

In my case, ECU was suspect of behaving defectively, so replacement was in order.

 

I didn't want some other ROM load that came on the ECU, I wanted just the opposite: my stock image put on the replacement ECU. So that's what I did. A dealer re-registration of keys, or EEPROM chip move (as I did) on the ECU .... in addition to flash programming the ROM image .. was required.

 

This wasn't a tuning hack, it was a "get the car operable again" play. For minimal dollars... accomplished by doing it myself, ebay for the ECU.. and no dealer visit.

 

I have all the right shop equipment for moving little 8pin SOIC chips from one board to another easily, in minutes was done. I would not recommend others learning how to do this the first time on their car ECU.

[xt2005bonbon]

scottmcphee, could you provide a picture of the old ecu and where that chip is located? Preparing for the future just in case

[mondtster]

Good if your existing ECU is in good shape, and I agree a new software dump onto your existing ECU is always going to be easier to do, and the preferred route... if you've got a good ECU.

 

Exactly, which is why I advocated this route from the start for the OP. Whe way I read his post, he perceives value in swapping the ECUs to hold onto one with an aftermarket file on it. I'm sure he wasn't thinking or aware of the immobilizer problem by doing that.

 

And, with the open source software and hardware so cheap and readily available I have a hard time understanding why someone wouldn't have a stock file and the ability to read and replace the ECU program easily. That, in my opinion should be required equipment when it comes to messing with these (or any FI) car.

 

scottmcphee, could you provide a picture of the old ecu and where that chip is located? Preparing for the future just in case

 

There are a few photos on the RR forums.

[scottmcphee]

RR = rom raider forum

[Truslide]

Which chip is the eeprom? I can solder it but I want to make sure i have the correct part... Thanks!! Pictures would be awesome!!!

[mikeyvt]

Sorry to bring this from the dead. So in the case that I wanted to swap ECUs I could in theory use a different ECU, same BIU, and keys but I would need the dealer to reprogram everything.

 

 

Sent from my iPhone using Tapatalk

[StkmltS]

Sorry to bring this from the dead. So in the case that I wanted to swap ECUs I could in theory use a different ECU, same BIU, and keys but I would need the dealer to reprogram everything.

 

 

Sent from my iPhone using Tapatalk

 

You are correct.

 

- or if you're good with soldering -

 

Open up both ECUs and swap the "security" chip from your current ECU to your new ECU.