Hello!
Senior Member
Joined: Apr 2021
Posts: 1,842
Likes: 25
From: Maine
As a former computer tech/service manager I can assure you (not certain assure is the correct word
) that any computer can be hacked.But any change to computer software leaves a trail, even the hacked ones.
The manufacturer will know someone has been in there and can easily prove this which means voiding your warranty.
A bit of advice for those who ever take a computer in for service, anything that was ever on any of the drives, can be fairly easily retrieved.
Unscrupulous techs/shops can do all sorts of things with that information.
Senior Member
Joined: Oct 2018
Posts: 10,515
Likes: 216
From: Northern California
The ECU on a car is not the same as laptops or home computers. When you get a "flash" it does wipe clean "all the original programing leaving no trace. Hacking however does leave foot prints mostly because the hacker no matter how good that person may be as a rule does not back up the ECU to have the original program in the evident that a "pass-through" needs to be done returning it back to the original programing or the last programing in the ECU which includes any counters and any other operating history of that ECU.
That was a direct question asked when I attended my EFI/ECU Performance calibrating School. My instructor's name was Greg Banish. The question of "footprint" or "trace" information being left if "flash or pass-through with the back up or OEM program would leave any trace of having been done. He explained that the misconception some have is that ECU on a vehcle is not the same as home computers or laptops not even cell phones.
So having done ECU calibrations on a professional level for close to 2 decades and having to return many back to OEM using the back-up ECU files because of either selling the vehicle or the vehcle having to return to a dealership for warranty service it has never been a concern.
Naturally in this ever-changing world that may someday change with new technology in ECU but not today!
Experienced calibrating ECUs only the following platforms:
Mazda Skyactiv 2014-2018 2.5
BMW
Chrysler(MOPAR)
FORD
Chevrolet
Suzuki (motorcycle)
That was a direct question asked when I attended my EFI/ECU Performance calibrating School. My instructor's name was Greg Banish. The question of "footprint" or "trace" information being left if "flash or pass-through with the back up or OEM program would leave any trace of having been done. He explained that the misconception some have is that ECU on a vehcle is not the same as home computers or laptops not even cell phones.
So having done ECU calibrations on a professional level for close to 2 decades and having to return many back to OEM using the back-up ECU files because of either selling the vehicle or the vehcle having to return to a dealership for warranty service it has never been a concern.
Naturally in this ever-changing world that may someday change with new technology in ECU but not today!
Experienced calibrating ECUs only the following platforms:
Mazda Skyactiv 2014-2018 2.5
BMW
Chrysler(MOPAR)
FORD
Chevrolet
Suzuki (motorcycle)
Senior Member
Joined: Sep 2019
Posts: 1,348
Likes: 20
From: North of Atlanta
The last post is another example to why only a designated thread should have been started. Now the OPs thread may go off into another direction then what you started it to be?
Auto manufactures (most) were aware this may happen and already were in the works (most)to have a system changed but may still be available or equip. Most auto manufactures reading technical updates will be the opposite of automatically having the feature instead of a manual on/off choice for the feature and off at all times unless manually changed,. This too be clear the owner/driver would need to manually choose to use the feature.
Unless in US there is a Federal Requirement that outline and clearly states that all manufactured vehicle's starting in 2027 or 2028 cannot have a start stop feature in any capacity sold in the USA then there may still be that feature on some models in various platforms? The new information does not stipulate what an auto manufacture can offer on a vehicle.
Hey I am all for all vehcle removing that start stop feature, but I read clearly what some information is and go to the exact source and not a (hand picked social media youtube that aligns with my thoughts and belief system) and often twisted social media (like the video posted in 2 threads today) by some that do not understand their meaning clear enough. Or did not research all the empirical data and information before posting it?
Auto manufactures (most) were aware this may happen and already were in the works (most)to have a system changed but may still be available or equip. Most auto manufactures reading technical updates will be the opposite of automatically having the feature instead of a manual on/off choice for the feature and off at all times unless manually changed,. This too be clear the owner/driver would need to manually choose to use the feature.
Unless in US there is a Federal Requirement that outline and clearly states that all manufactured vehicle's starting in 2027 or 2028 cannot have a start stop feature in any capacity sold in the USA then there may still be that feature on some models in various platforms? The new information does not stipulate what an auto manufacture can offer on a vehicle.
Hey I am all for all vehcle removing that start stop feature, but I read clearly what some information is and go to the exact source and not a (hand picked social media youtube that aligns with my thoughts and belief system) and often twisted social media (like the video posted in 2 threads today) by some that do not understand their meaning clear enough. Or did not research all the empirical data and information before posting it?
Senior Member
Joined: Oct 2018
Posts: 10,515
Likes: 216
From: Northern California
As a former computer tech/service manager I can assure you that any computer can be hacked.
But any change to computer software leaves a trail, even the hacked ones.
The manufacturer will know someone has been in there and can easily prove this which means voiding your warranty.
A bit of advice for those who ever take a computer in for service, anything that was ever on any of the drives, can be fairly easily retrieved.
Unscrupulous techs/shops can do all sorts of things with that information.
But any change to computer software leaves a trail, even the hacked ones.
The manufacturer will know someone has been in there and can easily prove this which means voiding your warranty.
A bit of advice for those who ever take a computer in for service, anything that was ever on any of the drives, can be fairly easily retrieved.
Unscrupulous techs/shops can do all sorts of things with that information.
To repeat so there is no misunderstand my level of information and knowledge on ECUs up to 2018 (because I have not done anything to an ECU past 2018)
I sent a Mopar ECU Mopar to the company that created the program for MOPAR after I had Calibrated it. They had told them up front I had made calibration adjustments in the ECU and that that after I had done the changes wanted to return it back to OEM to sell the ECU for exactly what the original programing was. The trouble was after I had returned it using the pass-through method which is the ECU is on the ECU passthrough equipment not on the vehicle, upon returning the backup oem file and connecting back to the vehicle to check it the engine would start but activated sever DTCs. No matter what I did I could not get the ECU to function properly I even attempted install the last ECU calibration file I did with no joy! He contacted me later to state the ECU was completely fine and there was no trace of ECU "ghosts" (traces of changing anything) and that the issue was a bent PIN connector.
.I remember specifically asking him the question so I can sell this an original STAGE 2 ECU then. His answer was yes there is NO trace anywhere that the ECU was ever changed from our original programing. And in fact, he also "school" me about the importance of making a back up ECU programing file for several reasons and that it would completely replace with all traces the original or problematic programing. His company also is known for refurbishing ECU,PCM.TCM in the industry both retail and for OEM . Looking at this information one could find who the company is and contact them and ask them directly about "flashing" an ECU and what remains to be found having done that?
Last edited by Callisto; Feb 21, 2026 at 10:20 AM.
Senior Member
Joined: Oct 2015
Posts: 701
Likes: 9
From: Madeira, Ohio
The bad thing about some of the newer vehicles is that they no longer even offer a disable switch that only temporarily disables the feature. Been reading more and more stories of people buying new vehicles and then finding there is no defeat switch.
Senior Member
Joined: Apr 2021
Posts: 1,842
Likes: 25
From: Maine
Very good information to remember about desk top computers and laptops for sure!
To repeat so there is no misunderstand my level of information and knowledge on ECUs up to 2018 (because I have not done anything to an ECU past 2018)
I sent a Mopar ECU Mopar to the company that created the program for MOPAR after I had Calibrated it. They had told them up front I had made calibration adjustments in the ECU and that that after I had done the changes wanted to return it back to OEM to sell the ECU for exactly what the original programing was. The trouble was after I had returned it using the pass-through method which is the ECU is on the ECU passthrough equipment not on the vehicle, upon returning the backup oem file and connecting back to the vehicle to check it the engine would start but activated sever DTCs. No matter what I did I could not get the ECU to function properly I even attempted install the last ECU calibration file I did with no joy! He contacted me later to state the ECU was completely fine and there was no trace of ECU "ghosts" (traces of changing anything) and that the issue was a bent PIN connector. .I remember specifically asking him the question so I can sell this an original STAGE 2 ECU then. His answer was yes there is NO trace anywhere that the ECU was ever changed from our original programing. And in fact, he also "school" me about the importance of making a back up ECU programing file for several reasons and that it would completely replace with all traces the original or problematic programing. His company also is known for refurbishing ECU,PCM.TCM in the industry both retail and for OEM . Looking at this information one could find who the company is and contact them and ask them directly about "flashing" an ECU and what remains to be found having done that?
To repeat so there is no misunderstand my level of information and knowledge on ECUs up to 2018 (because I have not done anything to an ECU past 2018)
I sent a Mopar ECU Mopar to the company that created the program for MOPAR after I had Calibrated it. They had told them up front I had made calibration adjustments in the ECU and that that after I had done the changes wanted to return it back to OEM to sell the ECU for exactly what the original programing was. The trouble was after I had returned it using the pass-through method which is the ECU is on the ECU passthrough equipment not on the vehicle, upon returning the backup oem file and connecting back to the vehicle to check it the engine would start but activated sever DTCs. No matter what I did I could not get the ECU to function properly I even attempted install the last ECU calibration file I did with no joy! He contacted me later to state the ECU was completely fine and there was no trace of ECU "ghosts" (traces of changing anything) and that the issue was a bent PIN connector.
.I remember specifically asking him the question so I can sell this an original STAGE 2 ECU then. His answer was yes there is NO trace anywhere that the ECU was ever changed from our original programing. And in fact, he also "school" me about the importance of making a back up ECU programing file for several reasons and that it would completely replace with all traces the original or problematic programing. His company also is known for refurbishing ECU,PCM.TCM in the industry both retail and for OEM . Looking at this information one could find who the company is and contact them and ask them directly about "flashing" an ECU and what remains to be found having done that?A vehicle ECU system, there are usually 30-40 in a vehicle but can be as many as 100 per vehicle depending on make (for controlling multiple functions) they all use the same coding languages C, C++, embedded C and low-level assembly language.
Most manufactures include some form of coding information (sort of like a safe combination) that can easily find any changes/rewrites/deletions/reloads that have been done.
While you may not always be able to find out exactly what was done a good could computer coding person will be able to know if the programming is not original.
And in the computer world 7+ years is an eternity (2018 to 2026) and currently some of the very latest ECU tools themselves, in proper hands are capable of doing this.
There should be no reason for any company who reflashes the ECU to even be looking for any changes as it has zero bearing on a reflash/reprogram and would be time consuming causing a detrimental effect on their profit line.
It makes sense to back-up any memory files but in reality, very few people every actually do it for any of their equipment that contains them.
Senior Member
Joined: Oct 2018
Posts: 10,515
Likes: 216
From: Northern California
Ok well I can't argue or debate with you comparing other then the subject of ECU on vehicles and the ECU world of those that actually build and program them differ with your information.
I know that it does not leave a trace when "flashed" over because you can measure the contents as you well know and not one amount changes from the original to the "flash"
I also will suggest its a none issue because not one dealership anywhere in the globe has any way to do what you suggest and also the best ECU Calibrators also in the world would not be able to find what is not their as you suggest nor would they IMHO even care to look.
I do trust and follow your information about computers other then ECUs on vehicles.
If I really thought, it would matter I would contact my source that actually builds programs as mentioned for ECUs and ask him. IF I do maybe I would post it but I can see where this would go. 2 computer experts debating their experience and information and one would not be a member of the forum to which I would have to be the carrier of back-and-forth responses. Been there done that having to do with a couple of members on another platform having to do with camshaft specification on a cam card.
Besides it is a no brainer to see that the membership on this forum is currently 78,568 and if 1 % of 1 % did any ECU calibrating that would be less than 10. But I will give it maybe 20 members? I know that not person ever since the dawn of OBD in 1995 ever was denied a warranty claim that any auto maker found guilty (proof of) of changing any aspects of a PCM or ECU and then "flashing " returning everything back to the last program or over writing the original programing from the auto manufacture.
I might add that in the chips were the big fad and many believed that simply plugging them into the ECU would leave a trace and that MYTH also died out. At least with the companies offering them that actually knew what they were doing and not the individuals that clone other company's chips and gave the aftermarket "chip" industry a bad name for a while.
I should mention that ECU some SKYACTIV ECU from about 2019 to preset and they have not been all found which specific model and or of those production years which exact VIN referenced ECU have a "flash counter. But a flash counter does not report anything except a number and currently is not a means of indicating that a dealer or unauthorized ECU changes in programing were done. The number also does not change the ECU volume so to the causal ECU inspection would no be able to claim if a dealer did a "flash" or others performed a "flash" and what the "flash was by ECU volume measuring and comparing to the original or current ECU information in the ECU itself.
So, in a nutshell at this point it is really meaning less as for information or anything that Mazda or other platform auto manufacture could use to deny and warranty connected to the phrase ECU tampering.
LOL I have to add... that those counters I mentioned a very experienced and trained EFI/ECU Performance Calibrators with the ECU calibration program that allows "GLOBAL ACCESS" to that ECU for the exact year and model Mazda (or other platform) can reset or change the number to anything they like.
Aftermarket ECU tunning programs do not always offer or have available unlocking the ECU for complete access to everything or called "GLOBAL ACCESS". I prefer to use those that do or I know how to completely unlock an ECU in all areas. So, this means that if a smart and talented calibrator wanted to completely keep the original information include the counter information one could do that.
It would be better if anyone in this subject material about ECU tuning at least have had basic ECU calibrating experience even just using an ECU program and only useing the "CANNED" ECU tune provided by the ECU tuning company like
For Mazda I highly recommend:
VersaTuner
This is one of the best companies for a Mazda and it easy to use with no experience in ECU tuning required, only knowing your way around you PC or laptop.
I know that it does not leave a trace when "flashed" over because you can measure the contents as you well know and not one amount changes from the original to the "flash"
I also will suggest its a none issue because not one dealership anywhere in the globe has any way to do what you suggest and also the best ECU Calibrators also in the world would not be able to find what is not their as you suggest nor would they IMHO even care to look.
I do trust and follow your information about computers other then ECUs on vehicles.
If I really thought, it would matter I would contact my source that actually builds programs as mentioned for ECUs and ask him. IF I do maybe I would post it but I can see where this would go. 2 computer experts debating their experience and information and one would not be a member of the forum to which I would have to be the carrier of back-and-forth responses. Been there done that having to do with a couple of members on another platform having to do with camshaft specification on a cam card.
Besides it is a no brainer to see that the membership on this forum is currently 78,568 and if 1 % of 1 % did any ECU calibrating that would be less than 10. But I will give it maybe 20 members? I know that not person ever since the dawn of OBD in 1995 ever was denied a warranty claim that any auto maker found guilty (proof of) of changing any aspects of a PCM or ECU and then "flashing " returning everything back to the last program or over writing the original programing from the auto manufacture.
I might add that in the chips were the big fad and many believed that simply plugging them into the ECU would leave a trace and that MYTH also died out. At least with the companies offering them that actually knew what they were doing and not the individuals that clone other company's chips and gave the aftermarket "chip" industry a bad name for a while.
I should mention that ECU some SKYACTIV ECU from about 2019 to preset and they have not been all found which specific model and or of those production years which exact VIN referenced ECU have a "flash counter. But a flash counter does not report anything except a number and currently is not a means of indicating that a dealer or unauthorized ECU changes in programing were done. The number also does not change the ECU volume so to the causal ECU inspection would no be able to claim if a dealer did a "flash" or others performed a "flash" and what the "flash was by ECU volume measuring and comparing to the original or current ECU information in the ECU itself.
So, in a nutshell at this point it is really meaning less as for information or anything that Mazda or other platform auto manufacture could use to deny and warranty connected to the phrase ECU tampering.
LOL I have to add... that those counters I mentioned a very experienced and trained EFI/ECU Performance Calibrators with the ECU calibration program that allows "GLOBAL ACCESS" to that ECU for the exact year and model Mazda (or other platform) can reset or change the number to anything they like.
Aftermarket ECU tunning programs do not always offer or have available unlocking the ECU for complete access to everything or called "GLOBAL ACCESS". I prefer to use those that do or I know how to completely unlock an ECU in all areas. So, this means that if a smart and talented calibrator wanted to completely keep the original information include the counter information one could do that.
It would be better if anyone in this subject material about ECU tuning at least have had basic ECU calibrating experience even just using an ECU program and only useing the "CANNED" ECU tune provided by the ECU tuning company like
For Mazda I highly recommend:
VersaTuner
This is one of the best companies for a Mazda and it easy to use with no experience in ECU tuning required, only knowing your way around you PC or laptop.
Last edited by Callisto; Feb 22, 2026 at 10:15 AM.
Junior Member
Joined: Feb 2026
Posts: 19
Likes: 4
Been reading through the CX-5 subforum for some time since purchasing my 2025 CX-5 in December. Been reading through the replies in this thread too.
One thing I'll add is that BMW 100% can tell if you've been flashing the DME. I don't know the exact details. But there is a flash counter that is stored in a permanent area of the DME. Even if you've restored the original factory tune, BMW will know the DME has been modified. This applies to both cars and motorcycles. Also, it's standard procedure to connect the DME in the car/motorcycle to ISTA which now by default connects back to the "mothership" at BMW to send data/telemetry.
There's been many threads on this at Bimmerpost and at the S1000RR forum where the beat to death horse of if doing a performance tune to a car/motorcycle while under factory warranty would jeopardize the warranty.
With my 135i, I've had the factory performance tune called the PPK installed in the car which provided an extra 20HP and 17 ft lb of torque. I later went to a Dinan Stage 2 tune. I felt comfortable doing the Dinan tune due to the history of Dinan and that they have in writing a warranty that will cover any issues related to their tune that BMW refuses to cover. With my S1000RR, I have as yet done anything to the factory tune. BMW Motorrad has a factory tune similar to the PPK which is meant to deal with the "hole" in the power band around 4k to 8k RPMs. It's supposed to boost torque and some power in that area but at the expense of top end power which drops to around 180HP from 205 HP. This hole in power is due to US EPA regulations. Currently, I have no plans to mess with the factory tune even though I have a set of Akra headers installed.
One thing I'll add is that BMW 100% can tell if you've been flashing the DME. I don't know the exact details. But there is a flash counter that is stored in a permanent area of the DME. Even if you've restored the original factory tune, BMW will know the DME has been modified. This applies to both cars and motorcycles. Also, it's standard procedure to connect the DME in the car/motorcycle to ISTA which now by default connects back to the "mothership" at BMW to send data/telemetry.
There's been many threads on this at Bimmerpost and at the S1000RR forum where the beat to death horse of if doing a performance tune to a car/motorcycle while under factory warranty would jeopardize the warranty.
With my 135i, I've had the factory performance tune called the PPK installed in the car which provided an extra 20HP and 17 ft lb of torque. I later went to a Dinan Stage 2 tune. I felt comfortable doing the Dinan tune due to the history of Dinan and that they have in writing a warranty that will cover any issues related to their tune that BMW refuses to cover. With my S1000RR, I have as yet done anything to the factory tune. BMW Motorrad has a factory tune similar to the PPK which is meant to deal with the "hole" in the power band around 4k to 8k RPMs. It's supposed to boost torque and some power in that area but at the expense of top end power which drops to around 180HP from 205 HP. This hole in power is due to US EPA regulations. Currently, I have no plans to mess with the factory tune even though I have a set of Akra headers installed.
Senior Member
Joined: Oct 2018
Posts: 10,515
Likes: 216
From: Northern California
A bit going to go off topic of this thread?
Dinan is a good company I use them on another platform. Not a big fan but it gets the basic's accomplished with a boosted model engine on another platform. They just have a lot of limitations for an advance experienced calibrator. They know me very well!
I also do professional tuning that cover several countries having customers on one model BMW, and I can delete the counters with no trace. But my experience is limited to one specific model and its years of production. As for the other info I fall back on the last response I made.
Bikes are slightly different when it comes to ECU tuning and really requires the use of a DYNO, EGT, EGA and data logging specific target RPM ranges when adjusting the ECU not just programs with theory calibrations. Or the trial-and-error method often pawned off as a professional ECU tune.
No I do not offer ECU tuning or advise as I have enough customers that keep me busy enough. There is forum dedicated for that out there. I rarely participate on then anymore to many wanna-be-tooooners and members that read a little bit about how to ECU calibrate and then think they can safely calibrate and just make a total mess of there ECU. LOL
Dinan is a good company I use them on another platform. Not a big fan but it gets the basic's accomplished with a boosted model engine on another platform. They just have a lot of limitations for an advance experienced calibrator. They know me very well!
I also do professional tuning that cover several countries having customers on one model BMW, and I can delete the counters with no trace. But my experience is limited to one specific model and its years of production. As for the other info I fall back on the last response I made.
Bikes are slightly different when it comes to ECU tuning and really requires the use of a DYNO, EGT, EGA and data logging specific target RPM ranges when adjusting the ECU not just programs with theory calibrations. Or the trial-and-error method often pawned off as a professional ECU tune.
No I do not offer ECU tuning or advise as I have enough customers that keep me busy enough. There is forum dedicated for that out there. I rarely participate on then anymore to many wanna-be-tooooners and members that read a little bit about how to ECU calibrate and then think they can safely calibrate and just make a total mess of there ECU. LOL
Last edited by Callisto; Feb 22, 2026 at 11:19 AM.
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Joined: Feb 2026
Posts: 19
Likes: 4
I went with Dinan at the time because my car was still under the new car warranty. My dealer was also a Dinan dealer but I got the DME flashed by an independent. At the time, Dinan or the factory PPK were the only options for my car due to BMW crypto locking the DME. MHD was out on the scene which allowed people to drop in off the shelf tunes or make your custom tunes. But at the time to use MHD required me to send them my DME to do a bench flash. Now they've worked out how to jail break the DME. I've only been causally reading about the newer BMW cars and it appears BMW has been able to really lock down the DMEs. Not sure f anyone has been able to jail break them. There are piggy back modules that function the same as a JB4 out for the new BMWs.
But the funny thing is I was an avid modder to increase performance on my performance oriented vehicles. I don't have that desire anymore as I've gotten older. I just buy the vehicle at the performance level I want factory and leave it alone.
On the bike side of BMW, many use those handheld programmers to flash the bike's DME with a performance tune. There's been lots of back and forth about how one particular company goes about their tunes. Some have confirmed this company disables any DTC trouble code reporting and logging. Woolich sells a system that allows you pretty much cart blanche access to the DME to make any adjustments you want. But it's not something I'm willing to mess with.
But the funny thing is I was an avid modder to increase performance on my performance oriented vehicles. I don't have that desire anymore as I've gotten older. I just buy the vehicle at the performance level I want factory and leave it alone.
On the bike side of BMW, many use those handheld programmers to flash the bike's DME with a performance tune. There's been lots of back and forth about how one particular company goes about their tunes. Some have confirmed this company disables any DTC trouble code reporting and logging. Woolich sells a system that allows you pretty much cart blanche access to the DME to make any adjustments you want. But it's not something I'm willing to mess with.
