ECU remaps - be aware...

Page may contain affiliate links. Please see terms for details.

merc07

Active Member
Joined
Jul 11, 2007
Messages
748
Car
C350cdi & C220cdi
When the tuner says they can reload you data if it is overwritten by the dealer - don't believe them, they can't - so DO NOT have it over written by Mercedes !

I paid £400 for a remap, it ran really well for a few years. It was later updated by an indy who told me it would most likely cure my on going disapearing eco problem.

The update cost £110 + vat - it made no difference to the fault but I later found out it was the dreaded emissions update, continuous regens, worse fuel consumption and no 7th gear until 75mph.

I sent it back to the original tuner who said they could do it no problem - they charged me £150
They said they had never seen the software before..
It turnes out all they did was put another map (not my original off the Dyno) onto the same software that the Indy put on.
I still had the issues as above.

The next day it over heated stuck in a regen for 40 miles and dumped all its oil everywhere - no way to prove it was the update though, maybe just a coincidence ?

£1800 to fix the oil seal, then another £400 from a different Indy to put right the work properly.

They had the ecu back again only to again tell me they have never seen that software before (second time they have seen mine??) and there is nothing they can do with it so just charged me the postage back - Another £20 in total

I am now using a standard ecu with no remap as I had a spare.

Not only have I lost £570 on the remap, maybe also £2200 because of it.....should never had done that original update !
 
2012 C350 diesel - I left out alot of the detail.....
 
Speak to MSL or GAD Tuning, perhaps they can advise
 
I always did wonder about this marketing claim , trouble is in reality they have to start from scratch and base a remap file on the existing , 100% if they have had a revised hardware sensor change .

I think it applies to certain makes , certain VW's , Mercs are more difficult for some reason .

I had a similar experience with an indie who thought a tune wasn't going to be overwritten by a software update...

Who's the tuner ?


Bet you missed that 700Nm .

They do piss oil for England from oil coolers you know .
 
Last edited:
Don't get me wrong, I was pretty sure the map would get over written, but I was so fed up with the ongoing stop start issue that no one, even Mercedes could fix that I let them go ahead - wrongly thinking I could get the tune re instated and not knowing the full outcome of the new Merc software.

The original tuner was MSL but he doesn't do diesels, they are farmed out to a third party...working remotely from his Dyno..
 
Just posted recently in " Engine V6 Diesel Update Software Recall". #'s 211@212, of my experience last March 20, and again last week, they don't give up. I must ask them, " What part of NO!! are they unable to grasp?". Good luck to you sir, you're gonna need it.
 
As mentioned, it can't be done, I'm stuck with the Merc emmisions map.
I could get my other ecu mapped, but after all the hassle I have had I need that to stay as is..and I guess cut my losses.

Possibly yes, Mercedes may have disabled the ability to load any files from their system that would downgrade the latest update. I wrongly assumed the software could be completely overwritten, not just the map files..
 
This might be obvious at this point - but there is a difference between Mercedes wiping your map and putting it back to 'stock' (as it was in 2012 maybe with some minor updates), and the 'new' Mercedes diesel emissions update.

With this emissions update the car's ECU is fundamentally changed by MB and so you can't just copy/paste the old map over the new one. It needs to be remapped again, properly.
 
Can I please just ask which MSL you went to (where was it) and when?


As an aside, regarding the ECO stop/start not working, commonly that's a lack of battery charge issue. Typical recommendations are:

- Properly charge current battery with a good charger (e.g. Ctek start stop, or MXS 5.0, although I would personally recommend disconnecting the battery from the car for the second choice).
- If you have an old battery, or not a Mercedes/Varta (same battery) or Bosch S5 battery, then get a new battery and make sure you have followed the step above after install before using it.
- If that doesn't cure it, then it's worth looking at battery drain/parasitic load/alteranator outputs.

Apologies if you have already been through all of those items.
 
It was Acid at MSL in Birmingham, can't fault them, they were very good, however as mentioned, the ecu work is done by a third party.

Re the eco, I fitted a new auxillary battery a while ago which made no difference.
Due to hardly using the car for nearly a year now due to furlough, I had to fit a new main as it wouldn't hold a charge anymore.
After that, the eco light came back on for a while, couple of hours maybe but soon went back to as it was.
Maybe as you mentioned, a drain or alternator output..
I leave it on charge permanently now but that doesn't help either...
It has been like this since 2015 !
 
I should add I took it to Acid originally a few years back, since then it went straight to the third party, I think 3 times..
 
Would be interested in who the 3rd party is , always nice to know who the author of the file is and quite often can assign a single name to it !

Leave non working SS as it is , your engine will thank you for it , I'm perplexed at the majority of Mercedes owners having the phenomenon of wanting this carnage contraption in working order .

Truely mind-boggling .


With the diesel roll back it's possible with VW's but not with Merc and BMW , so you have to start from the inferior update .
 
The tuner was 'Big Fish' was great before the update but all gone to pot since then.

I work in Bristol, before Covid I had a 1 1/2 to 2 hour commute, 21 miles, that's 45 to 80mins stopped..

Guess what you are saying is what I now figured after paying out, it is only possible to change the maps on a Merc ecu then, not the actual software..How come ?
 
It's parts of the software that is difficult .

The minnow heads are clearly not skilled .

Anthony at GAD is your only hope .
 
I'm also very interested in who the indi was who thought a software update would cure the Stop Strain issue ?

There's many things to rule out , even a brake vacuum sensor will prevent
20190723_173936.jpg



This is how to really fix Stop Strain on a 204 !


To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

And save 5Kg or disconnect a terminal lead or simply remove it's 7.5A fuse .
 
So where does the software controlling the ECU sit - on some EEPROM-type flash memory in the ECU?

If so, then replacing the ECU with one that did not yet have the emissions software updates applied to it, will put the car back where it was before the software update was applied?

And, you can then have the unmodified ECU mapped from scratch?

(The above wouldn't work if the software controlling the ECU actually sits in another module in the car).
(And, the above won't work if the new ECU needs to be coded to the car, but MB won't allow it to be coded unless the emissions update has been applied)

Disclaimer: the above is pure speculation on my part - I am in IT, but I know very little about MB Engine ECUs.
 

Users who are viewing this thread

Back
Top Bottom