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Discussion Starter · #1 ·
As many of you will know I have had the DPF and CAT removed from my car. The car runs well and the fuel consumption is very good, However I do have one problem. When I accelerate hard when the temperature is cold, damp or wet I get the engine light coming on. The code is P2453 which relates to theDPF which I know is not in the car and is supposed to have been written out in a remap. After speaking to the person who did the remap I have been told to get the ash content removed via the dealers diagnostic equipment. I know that I can reset the light myself however I would like to get to the bottom of the problem. I have been told that there should be probes under the car, my plan is to find them, insulate them and weatherproof them, has anyone else had this problem? PS my car does not go into limp mode, indeed I think that it runs better when the light is on!
 

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I had that after my DPF was removed. The chap who did it said it was a false zero or a nul code, wrote a bit ofsoftwareand no more problem. He did say that because they haven't done too many Captiva's it's still t the stage where they are developing theirknowledgeevery time they do another.
 

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Discussion Starter · #3 ·
Paul, the person that did the remapping after DPF removal has twice tried to sort the problem, it was he that told me about the ash problem! He is also going to find out more about the temp probes.
 

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On my car, there are 2 rubber pipes and 2 probes all bundled up to the metal ends of the pipes from the engine bay above the DPF replacement pipe. I did wonder if that was the issue with mine, but the software rewrite seems to have cured it. I wonder if the difference is that I still have the pre-cat- I only had the DPF removed. I'm not sure if there are sensors attached to that, but I'd be surprised of their weren't. Perhaps we should get together and compare?
 

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Hate saying this, but I said on another thread. Removing the DPF isn't the problem, modifying the s/w is.

I've been a IT consultant for over 25 years, and I would not trust a 'mechanic' to re-wright s/w, in the same way they would not trust me under the bonnet.

Hate to say this, but this may just be the start of your problems. The excuse of the ash seems to be bulls*** to me. Isn't that one the functions of a DPF to burn off residual ash. Can imagine what a Chevy dealer is going to say when you turn up and ask them to clear out the ash, as your DPF has been removed.

Guys, relly sorry to hear this, but it reinforces the argument not to remove the DPF for me.
Edited by: K.L.Richards
 

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Discussion Starter · #6 ·
K.L the vist to the dealer was already cancelled before reading your post. I know that they would have removed the ash by forcing a regeneration, this would be difficult as my DPF is in the shed! I will try to find the probes and insulate them from damp and cold. One good thing about not having to regenerate is that my engine oil is now far cleaner, I wonder if the regeneration process of dumping the cleaning diesel back into the sump is the cause of some of the engine failures.
 

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Good Question Evo, About dumping oil back into sump after 'burn out' of particulates.
I checked oil level yesterday on my brand new LTZfor first timealthough only 1600miles since new and the oil was very 'dark brown' - almost colour of black treacle! This surprised me to be so discoloured so quickly! Have only just returned to diesel after fifteen years petrol and I would go thousands of miles before seeing the 'golden oil' turn black with petrol. I am thinking that maybe an oil change would be beneficial to get rid of 'production rubbish' out of system. Views anyone?

Aussie Ed
 

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Diesel oil goes black very quickly. At 1600 miles, if it's not telling you to change it, I wouldn't. If you must change about 5000 when all of the initial running in is completed. I changed my oil a couple of weeks back and after 20 miles it was like treacle again.
 

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evo 370 said:
K.L the vist to the dealer was already cancelled before reading your post. I know that they would have removed the ash by forcing a regeneration, this would be difficult as my DPF is in the shed! I will try to find the probes and insulate them from damp and cold. One good thing about not having to regenerate is that my engine oil is now far cleaner, I wonder if the regeneration process of dumping the cleaning diesel back into the sump is the cause of some of the engine failures.

Is it not about a stored ash value in the ECU rather thanactualash, as if you have no DPF you can't have ash content in it!
 

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I agree iain, that's why I said I think the ash response was bulls***.

But as a professional in s/w developmnent, I stand by what I say about letting mechanics "bodge" s/w changes to the ecu.
 

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Discussion Starter · #11 ·
K.L. as far as I know the guys who write the progams are not the mechanics/technicians who install it into the ECU. The people who the public meet do not write the program they merely connect a laptop to the car, get the original ECU readings, they then send this electronically to the program writer who re-writes part of the program and this modified program is then sent back and reinstalledback into the ECU. Only once have I ever met the person who actually rewrote the software and that was for a Fiat and that was about 5 years ago, he also explained that not all ECU's could be reprogrammed.
 

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All I'm saying is that it is a specialist skill in writing comnputer s/w. From 25 + years experience in this field, which has seen me hold a role of senior consultant with one of the worlds largest IT comnpanies, and currently as a programme manager role with one of the UK largest IT companies, I can tell you that modifying s/w is extremely difficult and costly. A single code change can have thousands of implications, triggering different events. Testing these changes can take weeks or months. Please don't try and tell me tht the guys doing the changes are software engineers. They are hackers. They don't have to live with consequences of bad code, and I would bet they hvent tested it.

Check the internet. What these guys do, is to try and put code into the ECU, that sends signals to the ECU to fool it into thinking the DPF is still there. In yoûr case this has triggered a MIL code and put on the light.

You've had someone hack your ECU.

Look, I'm not looking to fall out here, but one thing I do know about is IT and s/w development, and it concerns me that these people are hacking ECUs. It could prove to be very dangerous.
 

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Discussion Starter · #13 ·
K.L. I agree the guys that we meet are not the engineers that write the programs, and indeed Paul the person from Angeltuning admits that it is someone else who earns good money rewriting / hacking into the ECU. However as I am someone who also works in the technology field and used to write programs myself I know that ECU programming although complex is probably not the most difficult thing to rewrite, afterall most cars use Bosch ECUs and thes guys seem to be able to understand the codes. We also drive an Audi A4, I tried to get our last Audi a A3 remapped, at that time Bosch had written anti tamper codes into it, however I now know that these codes have now been broken / rewritten and the latest Audi's can be remapped. My own problem is that I get a faulse code coming on when it is damp or cold and not when it is warm and dry, if it means that I have to occasionally attach my laptop to the car and reset the MIL it is not the end of the world. Afterall, my car gets excellent fuel consumtion, accelerates well, tows my twin axle caravan with ease, I do not have to dive it about 10 miles out of my way when driving the 3 miles home from my work when the DPF light comes on and when I come to sell it I can put it back to standard or if selling it privately offer it to its next buyer as a much improved product.
 
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