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Went to write a calibration using the latest beta............. no different then usual. It timed out on the write....... and now the ECM does not show up. Says unlicensed vehicle.
I've got a Tech 2, I hooked that up, the PCM/ECM is not present. Tried pulling battery, checked fuses............. IT'S DEAD.
Never had this issue before, what do I do? This is my womans car, need this fixed by tomorrow night........
*freaking out*......... BIGTIME
hmm...this is what im afraid of ,IF, and WHEN ever I get to be able to flash anything. im 0 for 2 so far on the interface allowing me in yet.
I got it sorted. So I would say it was battery voltage that caused the calibration write to fail midway.......... which bricked the pcm/ecu which was a E39 for reference.
Luckily I have a Tech 2 and MDI........ I figured given the stereo didn't have a 'no vin present message' and all the lights etc were working that the ECU must be working on some level despite the tech 2 not seeing it. So I jumped onto the SPS thing on ACDelcoTDS.
I paid for the 1 year 1 car thing cost about $60 AUD...... MDI picked up the ECU, reflashed it back to factory......... bang. Tried reflashing the calibration again.......... bricked half way again, repeated. The battery voltage was 12.2, 11.5, then 7.3 in the end.
Charged the battery, redid the write calibration with hp tuners etc - all worked fine. Odd thing, the MDI can flash the computer just fine with no voltage in the battery but the tuning software sh*ts itself....... there needs to be some tests run before HP Tuners flashes I recon to check voltages if possible. Dunno if the battery is F'd in the car..... might be, it's 6-8 years old but has never had a problem before, but hey maybe a cells died....... I'm sure I'll find out in the next few days.
My solution, in future......... battery charger hooked up while flashing....... to ensure the voltage doesn't dip. I got a charger that does 2A, 6A, 10A........ runs fine at 6AMP with the car all hooked up.
i have also down this with a TCM loosing voltage always have a trickle charger connected when flashing just to be safe
I thought it was a given that you would want a charger connected in the event some sudden draw took place. Take no chances and always connect a charger for good measure. There are actually special chargers for this for BMW. I would say this is common knowledge but heck I'll admit I've done it without a charger and have been lucky. Thank you for sharing your story and letting us know the fix/outcome was in thus case. It helps us all to learn a lesson. I am happy you got it sorted!
Thanks for sharing your experience. Hopefully it will save someone from frying their PCM. I trickle charge for a little bit before hooking up and flashing.