4HP20 2.2 C5

cachaciero · Post by **cachaciero** » 14 Jun 2010, 23:03

My auto box has taken to hanging on to second gear until close to 4K revs it then changes into third and then quite quickly into 4th.

The characteristics are akin to being in sport mode but sport mode is not selected.

Now if I drive it "manually" there is no problem goes up and down the box on command so I reason it has to be the brain rather than the mech bits however Lexia shows me nothing.

Any thoughts anyone?

cachaciero

wheeler · Post by **wheeler** » 15 Jun 2010, 09:03

Have you tried a software update on the autobox & injection ECU's ? or even try initialising the auto adaptives first ?

Post by **CitroJim** » 15 Jun 2010, 09:11

I'd look to try a reinitialisation of the auto-adaptives first. Looks like they've got a bit confused.

See if any faults are logged both in the gearbox and engine ECUs

The 'box relies on TC speed, engine speed, output speed and engine load to know when to change. If any of these signals are out of spec. or missing, the 'box will then use defaults.

When you reinitialise the auto-adaptives, take the car straight out for a good varied drive to get the retraining under way.

cachaciero · Post by **cachaciero** » 15 Jun 2010, 09:38

I've checked both engine ECU's and Gearbox for faults, nothing.

I've tried re-initialising the auto-adaptive bit that seems to have done little except that changes are a bit rough to start with and change points are sensible for a while but it seems to revert back, thinks!.... maybe thats after a restart.

Will have another go at that today.

Wheelers comments on re-programming are interesting I don't seem to have much luck with that on my Lexia. In manual programming It appears to allow programing of engine / injection combination plus there seems to be four options to with Town / declutching prohibition and other things which I have no info on at all and it is not clear what these are doing, nothing seems to get changed even if I try changing them.
Finally there is an implication that the injection ECU has to be programmed to match the box but again at least on the Lexia menu's it's as clear as mud which bits need to be looked at changed.
I would appreciate any explanation clarification of these areas.

cachaciero

wheeler · Post by **wheeler** » 15 Jun 2010, 10:35

What version of Lexia are you using ?
Its not programing, you need to go into the 'downloading' menu at the first screen & select the appropriate ECU. It will then search to see if there is a newer software version available, if one is available it will wipe & re flash the software. You shouldnt need to re configure the ECU's afterwards apart from maybe the oil counter, it would be advisable to make a print off/note down all the ECU configuration just incase though. Lexia will guide you through the procedure & tell you anything specific that needs to be done. The injection ECU should be checked for updates at the same time as the autobox & vice versa. Ideally the procedure shoud be carried out when the car is cold as you will need to do the initialising auto adaptives again after it.
Important bit- There is a risk that if the Lexia crashes or the lead is disconected during this procedure it could wipe the ECU completely, it is also recomended that you connect jump leads from another running car if there is the slightest doubt over the battery condition. Also i have never used or have any experiance with chinese clones so i cant comment on how reliable they are at this.

cachaciero · Post by **cachaciero** » 18 Jun 2010, 00:14

Well I have tried re-initialising the autoadaptive again and worked out that of the four options that can be set under the download menu's two are for ESP and two are no ESP which narrows the choice some.

Anyway on the one longish run I have done since doing this it would appear to be a little better in that it doesn't seem to hang on to second quite as many times as it did, like I only found myself reaching for the stick three times in 16 miles.

Set the Lexia up to record some parameters which shows clearly it being in second @3500K even when the Torque demand is decreasing which doesn't sound right. The one thing I would really like to know i.e which one of the n maps is it following doesn't appear to be available.

Wheeler

In answer to your question I'm using a lexia 3 with software rev 4.2 the box / dongle purports to be by Actia and I believe it is genuine.

Your comments about downloading from the internet I presume that one has to have some kind of account with Citroen for that ?

There are references in the Lexia to infodiag notes ref engine ECU configuration with autobox configuration which might be illuminating but unfortunately these appear to be on CD's DVD's which I don't have.

Rgds Cachaciero

cachaciero · Post by **cachaciero** » 20 Jun 2010, 18:51

Well I am sure that resetting the auto adaptive has not produced any result. Currently I am of the opinion that it is not just the change fro 2 to 3 being slow but also 3 -4.

I also have a suspicion that it might only happen when the box is hot.

As I said before it's like it's in permanent sport mode.

Thinks..... the Lexia tells you what mode is selected and it says eco BUT what is the Lexia reading the selector or what mode the ecu is actually in.

cachaciero

cachaciero · Post by **cachaciero** » 27 Jun 2010, 23:01

You can tell that the Lexia was designed by the French by virtue of the logic NOT.

Continuing the saga of gearbox investigation wanted to record various things over a journey like what gear is selected is torque converter locked up are these things under the gearbox menu? no! silly they are under the brakes menu ....? which if you set it up disables all the anti lock and stability controle how logical is that??.

On the subject of gearbox I have come to the conclusion that the only thing left to do is to re-flash it. This gives me a certain amount of trepidation bearing in mind wheelers comments but it has to be tried.
Now the thing that is not clear are the modules required on the lexia system (4.2) are they available on a CD which some one may have lying around or do I have to go to a stealer and get them to do this?

Advise on this subject very welcome...

cachaciero

Post by **xantia_v6** » 28 Jun 2010, 06:51

I can't see there being much benefit in re-flashing. Software doesn't wear out.

I think it is more likely that you have a sensor problem.

Footnote... I would like someone try flashing the updated Xantia 4HP20 firmware that apparently eliminates the 3000 RPM chnges when cold.

Post by **CitroJim** » 28 Jun 2010, 08:15

xantia_v6 wrote: Footnote... I would like someone try flashing the updated Xantia 4HP20 firmware that apparently eliminates the 3000 RPM chnges when cold.

Me too

It really, really annoys me. OK, I know you can mitigate it by poppping it into snow mode but it still niggles.

My Lexia refuses to believe there are any later patches for the ECU

If software never wears out, please explain Windows then

Why does a given level Windows software work fine for months on end and then suddenly need a service pack to keep it working?

Getting back to ECU reflashing, is it not possible for a few bytes here and there in the PROM to become corrupt over the years?

cachaciero · Post by **cachaciero** » 28 Jun 2010, 10:06

CitroJim wrote:

If software never wears out, please explain Windows then Why does a given level Windows software work fine for months on end and then suddenly need a service pack to keep it working?

Don't know use Linux myself except for the laptop which has Lexia on it.
that in itself is an appalling badly built bit of software has no less than four copies of some DLL's sprinkled around the application and they arn't all the same creation date, and when the application is terminated it doesn't release the USB port and clean up.

Getting back to ECU reflashing, is it not possible for a few bytes here and there in the PROM to become corrupt over the years?

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.

If that don't work I am somewhat stuffed. From what I have read the ECU on the C5 has 34 possible maps as opposed to the 10 on the V6 Xant but I have been unable to find any hard data on what these maps are and how they are allocated. e.g on the Xant the auto adaptive bit uses 6 of the ten maps the other four being used for low temp snow etc. 34 maps indicates an extremely fine degree of control. A technical manual for the ECU would be really usefull

I really am getting P.O with my C5, hard suspension left hand steering bias auto box high fuel consumption, although that may be related to gearbox as when I replace gearbox ECU with mk1 brain and left hand I can get figures which seem very close to those quoted by some "manual" owners. Life really is to short to spend hours and pounds trying to sort out cars all the time.

wheeler · Post by **wheeler** » 28 Jun 2010, 12:16

cachaciero wrote: Now the thing that is not clear are the modules required on the lexia system (4.2) are they available on a CD which some one may have lying around or do I have to go to a stealer and get them to do this?

I dont know which version of lexia you have as 4.2 doesent sound like a version. Lexia 3 started at version/disc 31 & the current version is 46. There are also intermidiate updates form the actia server in betweem major version changes. Do you have a CD/DVD disc with your Lexia ? On earlier versions of lexia (up till around 42) you could connect it to the actia server without any dealer login or password & do intermediate updates on the machines & remote updating of software on ECU's. If you can connect your machine to the net & do an intermidiate update on the lexia then you will be able to do a remote update of your ECU's via the actia server.

cachaciero · Post by **cachaciero** » 28 Jun 2010, 23:02

wheeler wrote:
cachaciero wrote: Now the thing that is not clear are the modules required on the lexia system (4.2) are they available on a CD which some one may have lying around or do I have to go to a stealer and get them to do this?
I dont know which version of lexia you have as 4.2 doesent sound like a version. Lexia 3 started at version/disc 31 & the current version is 46. There are also intermidiate updates form the actia server in betweem major version changes. Do you have a CD/DVD disc with your Lexia ? On earlier versions of lexia (up till around 42) you could connect it to the actia server without any dealer login or password & do intermediate updates on the machines & remote updating of software on ECU's. If you can connect your machine to the net & do an intermidiate update on the lexia then you will be able to do a remote update of your ECU's via the actia server.

Thanks for that info wheeler my Lexia is a 3 the software disk says 4.2 so maybe I stand a chance of getting on line, project for tomorrow assuming the wifi will go as far as the car

Out of curiosity as you are obviously "close" to Citroen have you seen / does there exist a comprehensive technical manual for this box or rather the ECU bit?

rgds cachaciero

Post by **xantia_v6** » 29 Jun 2010, 06:27

cachaciero wrote:
CitroJim wrote:
Getting back to ECU reflashing, is it not possible for a few bytes here and there in the PROM to become corrupt over the years?
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?

wheeler · Post by **wheeler** » 29 Jun 2010, 09:18

cachaciero wrote: have you seen / does there exist a comprehensive technical manual for this box or rather the ECU bit?

Im not sure if there is anything specific to the ECU functions or if it's just the basic technical manual.

Xantia_v6 wrote:Can the C5 transmission ECUs be swapped between cars, or are they one-time coded?

I dont believe the autobox ECU is matched to the car so there should be no problem swapping between cars.

Im no electronics expert & i could'nt tell you the difference between eproms,proms, flash & checksums but i do know that updating the software can quite often sort out problems like this. After checking basics I dont think there is much point in continuing looking for a fault untill you know that the ECU's that control the system with the fault have the latest software version available. I could give loads of examples of faults on PSA cars that develop randomly when the car as a couple of years old. The most common being engine management lights coming on with no fault codes stored, An upgrade of the ECU software usually sorts it.