ECU problem continued...

[keano]

Hi Guys,

Thought I'd update on the problem I've been having with my car.

The other day the 'Engine Management Light' & the 'ECP' light flashed up and stayed on.

Several faults registered from Throttle Flaps, to over requesting fuel, but the only error that could not be cleared was the 'Check Sum Error'.

Now I've had my remap taken off and the original file replaced, and the fault still registers and will not clear....so I've been told this points to the ECU.


I've been given different cures from different people so here goes:


**New ECU

**ECU update by Volkswagen (But they don't see any ECU updates on the VW computer   )

**& The option I have opted for.  Removing the ECU myself   and passing it onto an ECU specialist in Sheffield.



Has anyone had any experience of this, or offer me any other options?

All the best,

Nick  

[bacillus]

Hmm, is you car still under warranty?
Checksum error indicates an ecu problem to me.

[keano]

It's not no 

[PDT]

This may or may not help you, but hopefully it will let you understand the checksum process.

The checksum is a number (usually 8bit 4 digit code such as A8D7) and is a sum of all of the bytes of data within a piece of software. The ECU uses this checksum to verify the contents of a code or software version, i.e the ECU on the TFSi engine is an ME9 system and uses a 2048kb file and the data held within this file has a total sum which is validated by the ECU using this checksum code.

When this data is modified in any way, the checksum will need to be corrected, otherwise when the ECU looks for a valid checksum it wont be found and the car is unlikely to start.

Tuners use tools to read and write the data (the 2048k file mentioned above) to and from the ECU and when writing the data back into the ECU most tools will correct the checksum and there wont be any problems. Other tools dont correct the checksum and the tuner will need to correct it manuall by using a HEX editor such as Winols.

However, I have seen some ME9 ecu's which have been fine for years and no changes have been made to the ECU data and then all of a sudden come up with a checksum error. In most cases VW have an update to resolve this issue and most tuners (the ones that care and take tuning seriously) will obtain a copy of this update so that they can update customers ECU's to the latest software version available before tuning it.

Can I ask when your car was last in at the dealers? Has it been checked for available updates?

The reason the error may be present both with your tuned and original map is that its likely the tuned version is your original map with just a few maps altered to gain performance, the error is still there due to the data area causing the problem remains unchanged duringthe tuning process.

Im confident that the issue can be resolved via software alteration and a new ECU isnt required.

[vRStu]

There is a TSB which relates to an ECU update to correct the problem.  Don't know who your tuner is but Checksum Error can normally be corrected by them by loading a modified version of the updated file.

[keano]

Wow! Thanks for the replies 

Dealer hasn't seen the car for a long time. Although the systems brought up that no update was needed and everything was up to date.

Some things I could point out are that the original map I have on now is the one that was saved before anything was changed.

And also, relevant or not, when the 'Tuned map' was taken off the car too see if that was the problem, the 2048kb was only about 700kb i think, almost as if the ECU had altzheimer's and forgotten some of the code.

Does that make any sense?

[TrickGTI]

Mine did the exact same thing and it's a softwear update only but Vw do this for free but charge the 70 diagnostic fee for your pleasure even though I told them what was wrong with it! It will wipe any remap off your ecu to. 

[TrickGTI]

I go dig my invoice out and see if there is a recall number

[vRStu]

Grr - It won't be a recall!!

Why do sooo many people fail to appreciate the difference between a recall and a campaign 

24K6 rings a bell with me but I'd have to check.

[TrickGTI]

Yea I remembered it wasn't a recall after I wrote it but it's a free update anyways to resolve a problem that happens with them so it may aswell be a recall!

Anyway nothing on the invoice just says updated ecu Hope you get it sorted!

[vRStu]

so it may aswell be a recall!

Why??

[Saint Steve]

From memory, dealers only carried out the 24k6 update if the car was in for service.

It's not a recall.

[Hedge]

I have fond memories of 24k6 as that is the one my Skoda dealer flashed onto my ECU 2 hours after I went Revo stage 2.     

[keano]

So is that the solution then guys? 

[Saint Steve]

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