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Old 09-14-2013, 02:48 AM   #1
Chicago77
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Default ECU Flashing Clarification

So I have read a good amount about what I am about to ask over the past year, but I am trying to really iron everything out. I have a '13 wrx that is currently stock and I am about to add 22mm sway bars to even out the understeer as well as 5"muff nameless axleback (just a noise maker I know but the stock exhaust is just well... not what it could be) and I am thinking about buying an accessport at the same time (later I might go to stage 2 with a nameless exhaust but for now no other power mods).

Obviously the AP has the potential cause warrantee denial down the road on the powertrain. (doubt there will be a problem but one never knows).

From my reading it appears that uninstalling the AP would flash the ECU back to stock settings and the dealership would only be able to tell that the cars computer was flashed. I would love someone to verify this.

I also have read that disconnecting the battery also would also flash the ECU.
I think this is true.. as well.

So... if an AP was uninstalled could one simply tell dealership that the battery was disconnected if asked about the computer flash, or does the AP leave any residual traces in the memory?

From a computer science perspective unless the computer has some form of solid state memory disconnecting the battery for long enough should wipe everything. Or one should be able to go in and edit parameter values such as number of flashes. Thoughts?
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Last edited by Chicago77; 09-14-2013 at 02:52 AM. Reason: spelling :x
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Old 09-14-2013, 03:21 AM   #2
jt subie
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I have the feeling ppl are going to get on ur case about this one! lol. I personally believe that Cobbs stage 1 map is better for ur car than the stock tune and I'm pretty sure most will agree with me. warranty denial is just a risk u take if and when u start doing these types of modifications. Its up to u if u want to take that risk. there's plenty of threads about this with a whole bunch of opinions on if the dealer can tell or not. I think I'd be more concerned with having the dealer prove that a conservative stage 1 tune caused a problem
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Old 09-14-2013, 03:26 AM   #3
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The term "flashing the ecu" and relative forms actually refers to the process of writing a tune ( or map, as we call it ) onto the non-volatile memory of the ECU, meaning it's the map that is written on the hard drive of the ecu, conceptually...

Disconnecting the negative terminal of the battery, and flicking the lights a few times causes your ECU to reset. What this means, is that all of the things the ECU has learned to do, to protect your engine, will be erased. If you think of the ECU learned values as a Map... The map is the tune as it was written to memory ( flashed ), and if you marked down on the map all of the "gotchas" or "best way" to get somewhere... that would be how the ECU performs; it learns what additional fuel/timing adjustments need to be made, based upon all of its sensors' readings.

To answer the AP question...:

http://www.clubwrx.net/forums/tuning...uners-faq.html

"control + F .... " - 'Can a dealer detect'
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Old 09-14-2013, 03:27 AM   #4
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Quote:
Originally Posted by jt subie View Post
I have the feeling ppl are going to get on ur case about this one! lol. I personally believe that Cobbs stage 1 map is better for ur car than the stock tune and I'm pretty sure most will agree with me. warranty denial is just a risk u take if and when u start doing these types of modifications. Its up to u if u want to take that risk. there's plenty of threads about this with a whole bunch of opinions on if the dealer can tell or not. I think I'd be more concerned with having the dealer prove that a conservative stage 1 tune caused a problem
Im pretty sold on getting one either way, I might wait a little longer to make sure their aren't any lemon issues if I cant hide the map. I highly doubt the map will cause any problems which is why I am wondering if the dealer could tell. I am totally willing to pay if I break the car, but I dont want to get screwed for a mod that didnt cause the problem.

Last edited by Chicago77; 09-14-2013 at 09:55 AM.
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Old 09-14-2013, 03:31 AM   #5
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Quote:
Originally Posted by BeastianSTI View Post
The term "flashing the ecu" and relative forms actually refers to the process of writing a tune ( or map, as we call it ) onto the non-volatile memory of the ECU, meaning it's the map that is written on the hard drive of the ecu, conceptually...

Disconnecting the negative terminal of the battery, and flicking the lights a few times causes your ECU to reset. What this means, is that all of the things the ECU has learned to do, to protect your engine, will be erased. If you think of the ECU learned values as a Map... The map is the tune as it was written to memory ( flashed ), and if you marked down on the map all of the "gotchas" or "best way" to get somewhere... that would be how the ECU performs; it learns what additional fuel/timing adjustments need to be made, based upon all of its sensors' readings.

To answer the AP question...:

http://www.clubwrx.net/forums/tuning...uners-faq.html

"control + F .... " - 'Can a dealer detect'
So then I am correct in assuming that flashing a computer with battery disconnect will look the same to a dealer as flashing when uninstalling cobb?
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Old 09-14-2013, 06:03 AM   #6
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Quote:
Originally Posted by Chicago77 View Post

So then I am correct in assuming that flashing a computer with battery disconnect will look the same to a dealer as flashing when uninstalling cobb?
You can't flash the ecu with the battery disconnected if that what you're asking. When you flash you erase all learned "parameters" the ecu has changed due to input from sensors on the vehicle. Disconnecting the battery and purging the system of voltage, brake tap, will yield the same outcome because the ecu memory needs power to store information.

SOA will know if it really comes down to it 99% of the time.
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Old 09-14-2013, 06:47 AM   #7
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If flashing wipes system memory (sets memory gates to 0) and disconnecting the battery wipes memory (remove static charge in memory setting gates to 0) how will SOA tell the difference other than obvious signs of abuse which is unlikely to occur with a stage 1 map?

This is what I really don't get from what I have read on other forums. It seems that both actions simply wipe system memory. Which from a computer point of view would look the same if this is actually what is happening.
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Old 09-14-2013, 07:12 AM   #8
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Well for starters most dealer get suspicious when the car is bought in and readiness hasn't been completed. Also if a 16 bit is good for a 1000 flashes and 32 10000, there has to be a checksum somewhere that determines the flash number and or the original checksum has changed from what it was from the factory/dealer.
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Old 09-14-2013, 09:36 AM   #9
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Quote:
Originally Posted by JonnyV2889 View Post
Well for starters most dealer get suspicious when the car is bought in and readiness hasn't been completed. Also if a 16 bit is good for a 1000 flashes and 32 10000, there has to be a checksum somewhere that determines the flash number and or the original checksum has changed from what it was from the factory/dealer.
I own a WRX and I'm under 30... the dealer will always be suspicious lol...

I know that they can see the number of flashes is not what it was from factory.
Actually the counter seems to increment on reads too... But can they tell the difference between a battery disconnect flash and an AP flash.

I also am confused about why 16 bit is only good for 1000 flashes? I have seen it come up in a few places and it doesn't make sense to me. Memory should be rewritable pretty much indefinitely. The ECU rewrites constantly as it adjust to fuel, weather, car age.... Also 32 bit would go up on a scale of 2^n. Why does the number of flashes only increase 10 fold? In computer memory normally the value associated with the number of rewrites is an estimate of when the memory itself will fail on a hardware level not a software level.

If only Subaru would release this information
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Old 09-14-2013, 11:16 AM   #10
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Quote:
Originally Posted by Chicago77 View Post
I own a WRX and I'm under 30... the dealer will always be suspicious lol...

I know that they can see the number of flashes is not what it was from factory.
Actually the counter seems to increment on reads too... But can they tell the difference between a battery disconnect flash and an AP flash.

I also am confused about why 16 bit is only good for 1000 flashes? I have seen it come up in a few places and it doesn't make sense to me. Memory should be rewritable pretty much indefinitely. The ECU rewrites constantly as it adjust to fuel, weather, car age.... Also 32 bit would go up on a scale of 2^n. Why does the number of flashes only increase 10 fold? In computer memory normally the value associated with the number of rewrites is an estimate of when the memory itself will fail on a hardware level not a software level.

If only Subaru would release this information
Resetting ur ECU by disconnecting ur battery is not the same as flashing it. If it's true that they can tell which I think is likely I dont think it's going to look the same.
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Old 10-01-2013, 06:42 AM   #11
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Well I did finally get a pretty direct answer from cobb which if they are accurately telling the truth, and have a good idea what they are doing, would prevent subaru from being able to prove that it was installed.

-----------------------

Kyle (COBB Support)

Hi T,

I apologize for the delayed response. We are currently working through a large backlog of emails! To answer your questions:
How much of Subaru's ecu memory can you read from and how much you can write to?
All of it!
Is the ecu's checksum within the addressable memory and can you identify/write to this variable.
Yes!
If flashed back to the stock tune, does the AP rewrite the checksum to the original value that was stored before the AP was installed?
Yes!

-----------------------

This seems to indicate the only place subaru could hide logged data on their computer would be in the microchip registers (not sure if cobb included that in their definition of memory, I would doubt it). However this would be very inefficient and unlikely from a processing point of view as these bits are generally used to temporarily store commands and for memory addressing. Generally this is just used by the machine code after the compiler munches through the actual program subaru wrote.

Just thought I would report back on some of what I found.
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Old 10-01-2013, 09:17 AM   #12
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Bottom line is if, while at the dealership, the ECU is married to an Accessport (or ECU had been reflashed with a tune via any other solution), the dealership can certainly detect this, if they choose to do so. This includes changing the map to the "installed stock mode" map via the Accessport. However, with the version 2 or version 3 Accessport, a back-up of the ECU's ROM is created when you install so that exact ROM is restored when you choose the Uninstall option. This puts the ECU back to the exact original state it was in before you installed. However, any map change (including Accessport uninstall, map change or any other reflash solution) resets the ECU. The dealership does have the capability of determining that the ECU was recently reset (which clears all learned parameters). Of course, this could also occur if you disconnected the car's battery or reset the ECU via a common OBDII scanner.

That all said, we don't make any guarantees about whether a dealership can detect a previous reflash after you've properly uninstalled an Accessport. Subaru could be quite stealthy about how they implemented a flash counter external to the ROM that we modify. I'm not going to describe what those possibilities are. But, to date, we have seen no evidence that this the case. That doesn't mean it won't change in the future, but for now, the only warranty denials we've seen on an uninstalled Accessport is where the dealer indirectly guessed that via the ECU being recently reset or found other evidence that you had an Accessport such as finding the device, box, CD, cable, receipt or other hard evidence in the car. The reset ECU evidence is flimsy at best (as far as tying it directly to a reflash solution), but we have no control over how a dealership makes a decision on a warranty claim - they can do whatever they want and decide to deny a claim for any reason. That even includes completely bone stock cars that have never been reflashed - they can claim that you were abusing the car which caused the failure and deny the claim as a result. It would be up to you to fight it.

There are mod friendly dealerships out there. Check on your local forums to see if any of the dealerships near you could be mod friendly. That is no guarantee as it relates to any warranty claim, but there is a greater probability of things working in your favor than a dealership on the other end of the spectrum.

That all said, catastrophic engine or transmission failures are relatively rare, even at stage 1 or stage 2 levels. If you follow some simple guidelines, you can eliminate some common areas that can cause problems for you:

1. Never run an intake or other mods that is not supported by the map.

2. Get data logs whenever you start running a new tune or if something doesn't quite feel right. If you suspect or know something is seriously wrong, however, do not keep beating on the car with WOT pulls in order to get data - try to limit your high load pulls to the minimum needed to get the info (or know to cut run short where needed).

3. Use a high quality gasoline and make sure you are using the correct octane for the map you are using. You can also use a lower octane map with higher octane gas (where possible), if you want to stay on the more conservative side of things.

4. Keep up on your maintenance and fluid level checks (check oil level whenever you get gas or once a week). Use a high quality synthetic oil (see numerous posts on this topic - some synthetics work better than others for these motors). Do not extend oil or filter changes past the factory recommendation, even with synthetic oil.

5. Periodically (say every oil change) check your long-term fuel trims via the A/F Learning 1 A,B,C,D parameters (via Accessport's live data function). This can be done in your driveway with the engine idling (or ignition on engine off). Each individual value should be within around -8% to 8% for 08+ STi or -5% to 5% for other Subarus. If any one or more of these values is well outside of this range, it could indicate a mechanical fueling issue.

Bill

Last edited by Cobb Tuning; 10-01-2013 at 09:26 AM.
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Old 10-01-2013, 11:22 AM   #13
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I feel like bills reply to this should be stickied to the top. Very great explanation that it took me multiple forums to learn when I was first researching modding my wrx.
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Old 10-01-2013, 11:55 AM   #14
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This topic is beat to death ; The answer is the same. It's a gamble. You did your research, so you had your answer!

Sticky Bill's response. He must have that sitting in a word document somewhere for how often this comes up.
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Old 10-02-2013, 11:47 AM   #15
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Thanks for the post topic Chicago77. And thanks for the great answer Cobb!
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