[skyotee]

Okay, I am in a bit of a panic, hoping some of the experienced folks here can help! I went to do a stage 1 MHD flash on my 2012 335is today, and it failed and now my car won't start!

I used my galaxy s6 phone, and K+DCAN cable I ordered from **************.com (the reputable vendor everyone says to be these from). I checked the codes a couple times, and backed up the ECU successfully. So all good so far, cables & software seemed to be working fine. So, feeling ready to take the plunge, I paid for the flasher and stage 1 tune pack, and then connected my battery charger to the car, and selected the stage 1 flash. It said preparing ECU for about a minute, maybe two, and then said it failed. That's it, no progress bar, nothing else. And now the starter turns over, but the car never starts.

There were no error messages or signs of anything wrong on the dash, until I tried to start it unsuccessfully. At that point the service lift light came on. I tried re-flashing to stock, or stage 1, or pulling codes but they all fail. It just says failed to contact ECU no matter what. I have un-plugged and re-plugged, re-started phone, everything with the same result. The only thing I notice is when I plug the cable into the OBD port, the little amber LED lights up on the cable. It stays lit until I try to do something on the MHD flash, flash or pull codes, as soon as MHD tries to contact the ECU the LED on the cable goes out and then MHD says failed to contact ECU.

I also tried unplugging the battery for 30 minutes to get the ECU to reset and then tried to start the car, but no start. Tried MHD again, also no joy. I guess I will leave the battery disconnected overnight, and try again in the morning.

Anything else I can do? Am I going to have to go to the dealer with my tail between my legs and have my ECU reprogrammed?!

* I did email MHD for help also.

[NW 335i]

Find someone else w a cable near you and try again. Don't go the the dealer. There are location subforums here on e90post. Post up there. Someone will have a cable for you to try.

[BSM n54iS]

Originally Posted by skyotee

Okay, I am in a bit of a panic, hoping some of the experienced folks here can help! I went to do a stage 1 MHD flash on my 2012 335is today, and it failed and now my car won't start!

I used my galaxy s6 phone, and K+DCAN cable I ordered from **************.com (the reputable vendor everyone says to be these from). I checked the codes a couple times, and backed up the ECU successfully. So all good so far, cables & software seemed to be working fine. So, feeling ready to take the plunge, I paid for the flasher and stage 1 tune pack, and then connected my battery charger to the car, and selected the stage 1 flash. It said preparing ECU for about a minute, maybe two, and then said it failed. That's it, no progress bar, nothing else. And now the starter turns over, but the car never starts.

There were no error messages or signs of anything wrong on the dash, until I tried to start it unsuccessfully. At that point the service lift light came on. I tried re-flashing to stock, or stage 1, or pulling codes but they all fail. It just says failed to contact ECU no matter what. I have un-plugged and re-plugged, re-started phone, everything with the same result. The only thing I notice is when I plug the cable into the OBD port, the little amber LED lights up on the cable. It stays lit until I try to do something on the MHD flash, flash or pull codes, as soon as MHD tries to contact the ECU the LED on the cable goes out and then MHD says failed to contact ECU.

I also tried unplugging the battery for 30 minutes to get the ECU to reset and then tried to start the car, but no start. Tried MHD again, also no joy. I guess I will leave the battery disconnected overnight, and try again in the morning.

Anything else I can do? Am I going to have to go to the dealer with my tail between my legs and have my ECU reprogrammed?!

* I did email MHD for help also.

Instead of leaving battery disconnected, b/c you've already had it disconnected maybe leave the battery charger hooked up to the car for a while. Which battery charger btw? At least a 10 amp one I hope? You have your phone in airplane mode correct....with the car ignition on while trying to flash? Lights, radio everything still working with the car?

[Levanime]

U might had low voltage

Where r u located?

[JDuke335i]

Originally Posted by skyotee

Okay, I am in a bit of a panic, hoping some of the experienced folks here can help! I went to do a stage 1 MHD flash on my 2012 335is today, and it failed and now my car won't start!

I used my galaxy s6 phone, and K+DCAN cable I ordered from **************.com (the reputable vendor everyone says to be these from). I checked the codes a couple times, and backed up the ECU successfully. So all good so far, cables & software seemed to be working fine. So, feeling ready to take the plunge, I paid for the flasher and stage 1 tune pack, and then connected my battery charger to the car, and selected the stage 1 flash. It said preparing ECU for about a minute, maybe two, and then said it failed. That's it, no progress bar, nothing else. And now the starter turns over, but the car never starts.

There were no error messages or signs of anything wrong on the dash, until I tried to start it unsuccessfully. At that point the service lift light came on. I tried re-flashing to stock, or stage 1, or pulling codes but they all fail. It just says failed to contact ECU no matter what. I have un-plugged and re-plugged, re-started phone, everything with the same result. The only thing I notice is when I plug the cable into the OBD port, the little amber LED lights up on the cable. It stays lit until I try to do something on the MHD flash, flash or pull codes, as soon as MHD tries to contact the ECU the LED on the cable goes out and then MHD says failed to contact ECU.

I also tried unplugging the battery for 30 minutes to get the ECU to reset and then tried to start the car, but no start. Tried MHD again, also no joy. I guess I will leave the battery disconnected overnight, and try again in the morning.

Anything else I can do? Am I going to have to go to the dealer with my tail between my legs and have my ECU reprogrammed?!

* I did email MHD for help also.

Charge battery to 100 percent. When it's finished , pull the fuel pump fuse and flash again. If it fails it's most likely your cable

[skyotee]

Thanks for all the suggestions, I got it sorted out!

I did a couple things, not sure which did it. One, I switched to another phone, a Nexus 5. The other thing, I put the key in and hit the start button without having my foot on the brake. I don't remember if I did that before, since I was in panic mode when the car would not start.

I am guessing it was the second thing, not the different phone. I don't know why it failed to begin with, but after it would not start and seemed bricked, I probably was not as methodical as I should have been!

All is well now, so I guess I can join the main MHD thread now! Hopefully this might help someone else in the future...

[nukezero]

hold on, i'm interested to know how you got it fixed. as I am about to embark on this journey with my friend this weekend.

You tried to flash with phone #1 and it bricked. Then you hopped in the driver seat and tried to start the car? You believe, at this point, you didn't put your foot on the brake and therefore the car wouldn't start?

You went to bed and the next night, you woke up and tried a different phone but you also inserted the key this time and then put your foot on the brake and started the car, and it started?

So it looks like the flash didn't even start at all, it probably just errored out? Did it show how many percent you were at, till completion?

[TrollToll]

Originally Posted by nukezero

hold on, i'm interested to know how you got it fixed. as I am about to embark on this journey with my friend this weekend.

You tried to flash with phone #1 and it bricked. Then you hopped in the driver seat and tried to start the car? You believe, at this point, you didn't put your foot on the brake and therefore the car wouldn't start?

You went to bed and the next night, you woke up and tried a different phone but you also inserted the key this time and then put your foot on the brake and started the car, and it started?

So it looks like the flash didn't even start at all, it probably just errored out? Did it show how many percent you were at, till completion?

It sounds like he failed to turn the ignition on and that's why MHD failed to connect. With push-button you need to press twice without touching the brakes (until your gauges turn on).

[CarAbuser]

Originally Posted by atomic aces

It's normal for the light on the dcan cable to go off, at least mine always goes off after a minute or so and the connection holds up after just fine.

Have you ruled out the issue being with the female USB to micro cable?

I had one go bad on me but never during flash. I always set my phone down on the seat where it wouldn't move and didn't mess with it until after the write was complete.

The lights on my cable stay flashing the entire time. But they are Rx/Tx lights so it's mostly just the green Tx light flashing while it's writing then you get a blip from the red Rx light which I'm guessing is some sort of check or handshake.

[skyotee]

Originally Posted by nukezero

hold on, i'm interested to know how you got it fixed. as I am about to embark on this journey with my friend this weekend.

You tried to flash with phone #1 and it bricked. Then you hopped in the driver seat and tried to start the car? You believe, at this point, you didn't put your foot on the brake and therefore the car wouldn't start?

You went to bed and the next night, you woke up and tried a different phone but you also inserted the key this time and then put your foot on the brake and started the car, and it started?

So it looks like the flash didn't even start at all, it probably just errored out? Did it show how many percent you were at, till completion?

Not exactly. First flash attempt, I believe I did everything right, put key in and press start without foot on brake to turn car completely on without starting, then backed up the ECU. Next, I start the stage 1 flash, MHD said 'Preparing ECU' for about two minutes, and then said 'Failed'. At this point, I shut everything off & removed cable, then put in key, foot on brake, pressed start and the starter kept turning over but the engine would not fire.

Now, I am in panic mode, I just killed my car! Okay, so now I want to try flashing again, but I keep just putting in the key, which only brings the car half on, and try to flash, at which point MHD keeps saying 'Failed to contact ECU'. I keep doing this, and trying to start the car unsuccessfully, disconnect battery, rinse & repeat. All with the same results, no MHD, no start.

The next day, after the panic has subsided, I try again. This time, I don't bother trying to start the car I know wont start. I just put in the key, press start without foot on brake, everything turns on. And now MHD contacts the ECU, which it says is in recovery mode or something. First I flash back to stock, 38 long minutes later it is done, and finally my car starts!

Now I am feeling lucky, so I do the stage 1 flash. Which worked, and I have been enjoying the tune since!

[Thiago335i]

No hold up again cus now its my turn. I have a 2013 335is i got around a month ago already have jb4, downpipes and chargpipe with bov and i tried flashing my car yestarday and the EXACT same thing happend to me. Execpt after mine failed once the Jb4 backendflash while it was prepping ecu, as i tried again the flash would actually start but ALWAYS fail in the begging. Saying Error Code 7F 36 80 and another try it said Failed to Write ecu, paket 2 or something like that. My car wont start , it will crank but wont start and i have a billion dash lights on and i cannot even connect to my jb4 on the steering wheel. i have literally no idea what to do.
My buddy said that because my battery was low when i first attempted to flash is why it falied and i should let my battery charge. Please let me know on what to do my car was crazy yestarday morning and as soon as i messed with Mhd it completley disabled my car.

[rosullivan04]

Everytime I've had a failed flash I've been able to save it with flashing back to stock and a battery charger. Try flashing back to stock, put a charger on first.

[335e92tx]

Originally Posted by Thiago335i

.

Your profile says n55. Your not an N55 I hope. As you have an IS, I would think that's just a typo.
So, charge it over night, and then try it with charger still on.

[Thiago335i]

Yeah i just traded cars had a FBO n55 .. now just got my IS.. no typo But thankyou for the responses. It was actually my cable that would fail everytime the flash would try to start which i dont understand why, my buddy came with another OBD cable and it instantly flashed my car. Very angry because my first cable wouldnt even connect to the car to select what i was gonna buy, this other cable actually connected and thats how i bought my flasher module. Anyways All fixed hope people dont run into this problem its pretty scary when the car is inoperable. Thanks

[Izero]

you probably didn't put your phone in airplane mode... I did the same thing when I flashed my car the first time... and I was worried I bricked my ECU, but airplane mode fixed everything.

[Tangent]

I had difficulty flashing mine at first and finally worked out my troubles. First problem, sketchy cable. Bought the one from the recommended vendor and it at least communicated fine after that. Then once not being in airplane mode killed it. Then began the real frustration with failed attempt after failed attempt. What finally resolved it was using a different device. It simply wouldn't work with my Motorola Droid Turbo 2 but it's been working flawlessly on my Samsung Galaxy Tab. If you have another Android phone or tablet give that a shot.

[jasonytl1]

Hi, I am from Hong Kong, I have did a lot of review before try to flash my car with MHD, and I finally decide to flash it today, but my flash didn’t went well and my car can’t turn on anymore, this is the process of my flash, hope that you can help me.

First, I have my battery connected to my car, then I pug in the K+DCAN cable, it connect successfully, I purchases the flasher module and stage 1 map, then I go backup my ECU and start flash the map. Firstly it go well, but then it stuck at (15%, 31min) left. I wait for more than 1 hour but it still stuck at 15%, so I have choices to unplug the cable, then I restart the phone and ofcause my car can’t start anymore.

After my phone restarted, I try to flash my car back to stage 0, the MHD app go well and start flash back to stock, later on, it stuck at (89% 2min) left again, after half hours, I have no Choice to unplug the cable again. Finally, the MHD app no longer connects to the ECU, I try with the same cable that I have used and it said no cable detected. That is all the process of my flash, hope that you can give me some help, thanks.

[2007BMW335i]

Make sure your battery charger is at least 10 amps or connect to another running vehicle with jumper cables. Make sure your phone is in airplane mode. Disconnect the D-Can cable from the car and reconnect it. Make sure your climate control and auto lamps are off and the doors are closed. Push the start button once for accessory then again to turn on ignition/DME with foot off the brake, Set the phone down start flash and do not move it during the flash. If this doesn't work try another android device using the same google account.

[jasonytl1]

Originally Posted by 2007BMW335i

Make sure your battery charger is at least 10 amps or connect to another running vehicle with jumper cables. Make sure your phone is in airplane mode. Disconnect the D-Can cable from the car and reconnect it. Make sure your climate control and auto lamps are off and the doors are closed. Push the start button once for accessory then again to turn on ignition/DME with foot off the brake, Set the phone down start flash and do not move it during the flash. If this doesn't work try another android device using the same google account.

I know, but now I can’t even reach the flash page, it just said no cable detected, how can I solve it

[Tunafish]

Did this get fixed?

[Killca_cze]

we had same problem on friends 335i e92, trying to load MHD Stage 1+ map to ecu (there was stage 1 already installed on race circuit because 1+ was overheating the engine) through my iPhone XS and MHD Wireless adapter and it connected to cable, but after 7% sent an error and car didnt want to start, so we unplugged battery for a minute and then used android phone with same account (without trying to start the car) and it worked well and after that it started just fine. You may try the same, use another device or after that even a cable instead of wireless adapter.