The perils of self flashing......

[psmart]

Picture the scene.... you've had your car tuned (eeprom remapped)... you've acquired a KWP2000 OBD re-programmer... you have the original map + the tuned map... your car has a turbo fault, so you want to re-program to the original until its fixed... You depend on the car too much to take a risk, but you keep going down to your baby several times to re-program and chicken out at the last minute....

Car is now not in use, awaiting its MOT... weather is ****e... so you decide to take the gamble... and re-flash... Like coming up red on the Roulet wheel when you bet on black, the odds were stacked against you and you fry your ECU... car becomes an effective paper weight

Luckily, all is not lost! The German tuners, www.ml-chiptuning.de, Duisberg branch, who originally tuned the car were very helpful (I've found the Germans to be incredibly helpful), took the ECU, desoldered the PSOP eeprom (29F800), re-flashed it, re-soldered it and EUR75 later, car is no longer a paper weight!

So, advise:
1) If you use a KWP2000 OBD programmer or similar, YOU MUST disconnect all heavy consumers of power - ie. Engine Fan.
2) Dont muck around with 'Ebay Tuning files', only a small portion of the EEPROM data is engine parameter data, the remainder is the Siemens Infineon C166 (microprocessor) software program. I have many for the ML and they all differ extensively. Let a tuner take your original, change the parameter data, and create you a tuned map.
3) If you do blank out (fry) the EEPROM, you need to acquire an SMD de-solder station, very expensive, or a company with one that is willing to de-solder, re-program and re-solder the EEPROM.

Mercedes ECU design fault:
Generally, as a rule of thumb, when you design a microprocessor control system, you make them 'consumer safe' in the reset, watchdog-reset or boot loader modes. Mercedes havent done this, so when you set the ECU into reset/boot loader mode, several things 'switch on', such as the cooling fan!!! Imagine an ECU failure at speed, and everything switches on, such as Injectors!!! Gulp! Bang!

 

[television]

desoldered the PSOP eeprom (29F800), re-flashed it, re-soldered it and EUR75 later, car is no longer a paper weight!

[

Mercedes ECU design fault:
Generally, as a rule of thumb, when you design a microprocessor control system, you make them 'consumer safe' in the reset, watchdog-reset or boot loader modes. Mercedes havent done this, so when you set the ECU into reset/boot loader mode, several things 'switch on', such as the cooling fan!!! Imagine an ECU failure at speed, and everything switches on, such as Injectors!!! Gulp! Bang!

That's cheap, it cost me £30 to have the 290 pin + IC's removed and replaced, making a repair hardly viable when you include postage, I found the same expertise in Sweden, even all of the colleges had all of the know how and gear


There are two parts to these systems, the micro and the output control, in the case of the Micro,these can just loose data or give out goble de gouch, Output/drivers normally go short circuit, often taking down the whole thing. S/C output semiconducrors go down, leaving the output High, or at +v as under normal conditions they ground the object that they are driving, leaving most things safe.

When I read your headline, or thought that you had been doing something rude



Malcolm

 

[psmart]

That's cheap, it cost me £30 to have the 290 pin + IC's removed and replaced, making a repair hardly viable when you include postage, I found the same expertise in Sweden, even all of the colleges had all of the know how and gear

Yep, thats what I thought, very helpful to the bargain, so Im taking my Motorhome ECU to him as I want to ditch the external power box I currently use.

There are two parts to these systems, the micro and the output control, in the case of the Micro,these can just loose data or give out goble de gouch, Output/drivers normally go short circuit, often taking down the whole thing. S/C output semiconducrors go down, leaving the output High, or at +v as under normal conditions they ground the object that they are driving, leaving most things safe.

Assuming a part has failed, makes perfect sense, but microprocessors can go awol without reason, hence the watchdog-reset circuitry to hold it in a state of reset dependent upon fault. In the reset state, nothing should be powered up, assuming all output drivers etc are fully operational. But in the case of my ECU and from my discussions with ML ChipTuning, most other Merc and VAG, this is not the case. Perhaps they designed it such that if the ECU failed, the fan would come on in, but I cant think of a reason why.

When I read your headline, or thought that you had been doing something rude

Rude.... moi? I just have to write the word Microsoft (a swear word in many a household) and the mod-ariators blank it out

 

[psmart]

Just to add some info to this post, for others in the same situation:

When I blanked (fried) the ECU eeprom, I contacted the following ECU companies, along with responses I obtained:

www.evc.de - could sell me the equipment to sort the mess out myself (expensive).
www.tunemycar.com - never bothered replying.
www.ecuexchange.biz - Couldnt do the work.
www.bellautoservices.co.uk - Incredibly helpful man, new his stuff and would definitely recommend. If the original tuners hadnt been able to help, I would have chosen this guy.

 

[ALAN@ECUCLINIC]

ecuexchange ....couldnt do it?!!! shock horror i only left there 2 months ago and up till then they could!!!!!

 

[psmart]

To quote there email....

sorry we cannot help you with this one try atp 01543 467466


www.ecuexchange.biz

...sounds like you were THE engineer there, or they just couldnt be bothered!

 

[ALAN@ECUCLINIC]

try atp?!!!!! why? un,****** ,beleiveabubble!
oh well all the more for me then i repair hfm and pms,if you need me,call me,no matter how far, no matter who you are, and i will be there in a hurry!!!!

 

[psmart]

Pictures of an ECU...

Just for your info, pictures of an ECU ... and the chip which needs replacing if you blank it....

The chip is a 29F800, located in the lower right corner, the one which only has legs on 2 sides. Its in a packages called a PSOP and requires a Hot Air or Infrared rework station to remove. The EEPROM is a 1MByte Electrically Erasable Programmable Read Only Memory.

Notice the 2 legged blocks on the left hand side... these are your injector transistors, if an injector misfires, and it isnt the injector or wire, this is the beauty to replace.

The Mercedes model type is: EDC15C6.

 

[psmart]

...and just for comparison

...pictures of my Motorhome ECU... the one required for controlling all the ancilliary living circuits....

....now Malcolm ('Television').... dont balk.... point to point wiring, for me is the best prototyping method until I get round to designing a finished circuit board