4HP20 2.2 C5

cachaciero · Post by **cachaciero** » 29 Jun 2010, 17:53

xantia_v6 wrote:
cachaciero wrote:
CitroJim wrote:

That.s what I am thinking. Without knowing just how much of the S/Ware is in hard rom and how much is in flash it is difficult to be sure of anything. However for sure the basic MAPS will be in flash.
Firstly, I am sure the firmware in flash would be check summed and checked at boot-up, to detect a failed re-flashing.

The next thing is that flash memory is VERY stable and reliable once it has been written, I can't remember hearing of a random data corruption in flash (ignoring issues related to wear-out and the process of writing).

Wear-out of flash can be an issue, but that is related to the number of write cycles of a location (100,000s), and is unlikely to be an issue here, as software that writes data to flash uses wear-out avoidance techniques (and some chips perform this in hardware) to extend the life to millions of write cycles. In any case, if you have a flash wear-out problem in the data area, then re-flashing is not going to help.

It is possible that some data variable or counter that is stored in flash ha become corrupted, due to a power glitch while writing etc, but if the Lexia reset did not fix this, then re-flashing is not likely to either, because re-flashing probably doesn't overwrite the data areas of flash.

Can the C5 transmission ECUs be
swapped between cars, or are they one-time coded?

Yes I can't argue against what you are saying it is logical but the ECU writes a lot semi permanent data to somewhere , valve /pressure reg characteristics and auto adaption data, does it put this in flash? or maybe maintained ram I don't know. What I do know is that the Lexia doesn't tell me the things that I really want to know like what map has it elected to use and what sportivity index is it using as part of it's adaptive function so I have no way of knowing if things are logical or illogical apart from the fact that hanging on to second gear to 4k on a level road and trailing throttle is definetly pants.

I am though not convinced that it does a memory checksum check before powering up because if any data is changing and I believe some does then it would have to do a checksum calc and write after every valid change and I have doubts whether the software is that professional.

cachaciero

cachaciero · Post by **cachaciero** » 29 Jun 2010, 18:07

O.K today we tried downloading to the box as per wheelers suggestions, in a word it didn't work.

The downloading updating of the tool appeared to work at least it gave me a choice of CD /S/W versions to update. it did however want something called an RRID number I made one up and it "seemed" to take that.

However when it came to updating the box software it appears to download something and then comes back and asks me for a Psa service login and password which of course stuffed me.

I then tried doing it locally, listing the dowloaded packages indicated that there was available a module with the same ver number as was apparently loaded into the ECU. However when trying to get it to go it just came back with words to the effect that there wasn't a version newer than that in the box therefore there was nothing to do! one laptop almost ended up the other side of the drive!!!! Don't really know if that was because it wouldn't do it because of same version number or maybe the module isn't on the Lexia anyway it's not very clear.

So is there anyway of forcing the thing to re-write the same code to the box?

Basically I am no further forward on two very annoying problems i.e g/box and hard front suspension and I am getting just a tad cheesed of.

cachaciero

cachaciero · Post by **cachaciero** » 02 Jul 2010, 11:59

Wheeler where are you? please tell me how I can force a download to the box with the same level of software that it already believes that it has?

cachaciero

wheeler · Post by **wheeler** » 02 Jul 2010, 12:31

Unfortunately there is no facility in Lexia to reinstall software if it is already up to date. Can you do the intermidiate updates on your lexia online ?

cachaciero · Post by **cachaciero** » 02 Jul 2010, 19:32

wheeler wrote:Unfortunately there is no facility in Lexia to reinstall software if it is already up to date. Can you do the intermidiate updates on your lexia online ?

What intermediate updates? as far as I can tell my bosx has the latest software available for a 2001 4HP20 there is as far as I can see nothing newer.

As regards doing stuff on line currently no because it is asking me to login to a PSA site for which I have neither login or password.
although I have an account on service.citroen.com it won't accept the login that i use for that site so I guess it's a special Lexia server?.

If I accept that the citroen tools have noway of re-downloading to the box then basically I am stuffed because I assume that if I take it to a dealer they will say sorry guv new box ecu that can't be right...can it.

cachaciero

h2ocooler · Post by **h2ocooler** » 02 Jul 2010, 22:04

Dont know if this is the same or would help.

http://cgi.ebay.co.uk/CITROEN-C5-AUTOMA ... 563c16c990

Rob

h2ocooler · Post by **h2ocooler** » 02 Jul 2010, 22:06

Only other thing I could suggest is IF the gearbox ECU is not coded to the car then if it come to it we could try My ECU if its the same.
Rob

cachaciero · Post by **cachaciero** » 03 Jul 2010, 22:23

h2ocooler wrote:Dont know if this is the same or would help.

http://cgi.ebay.co.uk/CITROEN-C5-AUTOMA ... 563c16c990

Rob

Hi Rob

Don't know is the answer the docs I have say that it is the same ECU for both rhe 4HP20 and the AL4 not sure I would like to put my money on that

. Anyway I have asked for further details. Interestingly the part number he quotes does not appear on the Citroen parts list amd while they list an EXU for the 4HP20 they don't for the AL4.

cachaciero

cachaciero · Post by **cachaciero** » 03 Jul 2010, 22:40

h2ocooler wrote:Only other thing I could suggest is IF the gearbox ECU is not coded to the car then if it come to it we could try My ECU if its the same.
Rob

That's good of you Rob but I would worry that we could end up with two units that are not right. You see I have a sneaky feeling that all this trouble started after disconnecting the battery one day.

I wonder if I can tell the lexia that it is a different car one that happens to have a 4HP20, with a different load V6 for example and get it to download the software for that then start again but this time for the correct car . But before I do that it would be nice to have a spare ECU to hand.

cachaciero

cachaciero · Post by **cachaciero** » 08 Jul 2010, 19:53

Well tried to tell the Lexia that it was hooked up to a V6 and would it kindly download to the autobox ECU.. no! it wasn't having any of that, came back and said the software was upto date......?

Now that struck me as a bit strange as I feel sure that the gear / speed mapping on a V6 would be different to a 2.2Hdi. so how could it be upto date in-fact how could it even be the right code for a V6.

After a bit of thought came to the conclusion that it must look at the injection ECU to find out whether it's a diesel or not...b.gg.r! the injection ECU's are definitely different V6 to Hdi

As an aside can anyone tell me where to find the autobox ECU?

cachaciero

wheeler · Post by **wheeler** » 08 Jul 2010, 22:07

cachaciero wrote:
As an aside can anyone tell me where to find the autobox ECU?

cachaciero

It's in the same compartment as the under bonnet fusebox & the injection ECU.

cachaciero · Post by **cachaciero** » 08 Jul 2010, 23:19

wheeler wrote:
cachaciero wrote:
As an aside can anyone tell me where to find the autobox ECU?

cachaciero
It's in the same compartment as the under bonnet fusebox & the injection ECU.

Ah! I was in there this afternoon changing a blown Maxi fuse for the BHI didn't recognise it guess it says gearbox ECU in German:-)

Thanks wheeler.

cachaciero · Post by **cachaciero** » 14 Jul 2010, 11:05

Well this saga continues I can find / see nothing obviously wrong.

Decided that the time has come to find a real auto-box specialist and talk to them.
Now there doesn't seem to be so many of them but in the end chose to talk to one of the most prominent in terms of Web presence in the South East Area. Talked to a nice chap who said:- "got to be external" throttle or speed inputs" well that's something that has been suggested here I have looked at it and can see nothing obviously wrong, which is not to say that there isn't as I have seen reference to the fact that there can be problems with speed sensors that Lexia will not pick up.

Anyway my interest was whether they had facilities to re-flash the ECU "that's not usually possible" says the man "and if they are we have to go to a main dealer" he then asked me what box we were talking about " ah! 4hp20 not a very common box that" ....?

to the question do you have many problems with ECU's the answer was none.

Upshot was that they wanted £45.00 to analyse the problem.
Now I just get the feeling that at least at a control level they know less than I do and I am not going to get much further forward investing £45.00 with them. Thoughts please?

Anyway last night on the drive home the box evidently knew it was the subject of discussion because it was completely different ,it was consistently selecting higher gears right from the off and only toward the end of the journey did it start hanging on to second.

This on a regular journey of about 16 miles consumption normally 30 last night 32.0 and I only had to reach for the stick three times (apart from the times I needed to confirm the gear why oh! why didn't they drive the gear indicator lights in auto?)

I have noticed that often starting from cold the box usually seems to work o.k for the first half mile or so after which hanging on second starts to happen more and more.

My gut feel is that it is the ECU I notice that the ECU seems to run very hot and there is little or no natural cooling where it is installed and last night or rather early this morning it was a little cooler than of late.

Undecided do I punt on a secondhand ECU or pay for a "specialist" to give their opinion?

cachaciero

cachaciero · Post by **cachaciero** » 15 Jul 2010, 15:14

Box seems to be working properly today short journey circa 8 miles.
goes into third at 2300 revs light throttle a treat every time on the level or downhill hangs on a little going uphill but I would expect that.

It is cooler today than of late.

cachaciero

Post by **xantia_v6** » 15 Jul 2010, 21:31

Well I still think it sounds like a sensor fault. I don't think it is likely that an ECU fault is giving the symptoms you are describing.

Does the transmission ECU get its engine load signal direct from the throttle, or via the injection ECU? I suspect that the latter is more likely.