Engine ECU Kaput after Battery Change?

[Terrytraveller]

How many forum members/readers have experienced ECU or other problems after battery has been disconnected or changed ? As an example have a peek at the Morocco posting and Myspeaks remarks.

 

I have read somewhere but cannot find the article now, there is a ECU shut down procedure before disconnecting the battery. I remember the advice was – “ before switching off the engine, release the bonnet catch, open the driver window, close the cab door and switch off engine by reaching through open window. On no account open the driver door as this wakes up the ECU again from its shutdown.”

 

According to Myspeaks account of the problem, when the battery was disconnected all customised settings for that particular vehicle were lost, default (and incorrect) settings are read back into ECU memory upon reconnection of vehicle battery. Apparently there is no battery back up internally for the volatile memory, you would think it would be saved to non volatile memory for example, memory that can retain data without battery backup(EEPROM).

 

Has anyone disconnected or changed the vehicle battery on 2004 Peugeot 2ltr Hdi ?

 

I changed vehicle battery on a 1998 Fiat 1.9td without any problems.

 

Regards Terry

[enodreven]

Hi, this may help

 

http://www.fiatforum.com/ducato/79425-ducato-key-code.html

[Terrytraveller]

Hi Brian,

 

Thanks for the reply, had a look at that Forum, frightening what can go wrong with a simple battery change isn't it?

 

I searched Google under ECU shutdown procedure and came up with the article I thought I had lost at

http://www.bodyshopmag.com/features/feature.php?id=2074

I wonder if that advice applies to all modernish vehicles.

 

Regards Terry

 

 

[tonyishuk]

The Ducatto forum mentions a button by the battery.

 

Only thing I would add AND IT IS USEFUL TO KNOW, is that the button by the battery is a safety cutout button that turns off the electics in case of an accident.

 

I belive it is inertia driven so a vey sudden stop ( or drop) can operate it and close down the vehicle electrics. (Hit a traffic buimp too hard !)

 

A small press on the top will set back to on.( and hopefully normal service is resumed)

 

 

[chas]

Hi Terry- About 12months ago I had occasion to trickle charge my Pug 2ltr 05 van after it went flat, when I thought it was being charge on hook up to the leisure battery, ( this as now been sorted) and ignorance being bliss, disconnected the earth, would have done the positive, but too much was involved getting to it,( no room) after a 2hr charge reconnected and everything worked fine.

 

So any shut down procedure did not worry my ECU (this time). chas *-)

[Guest peter]

On my Toyota Supra if battery is disconnected you have to drive it for a few miles before the ECU re-learnes your driving characteristics.

[Basil]

Funnily I was talking to my wifes Farrier this morning and he was telling me he had just had to change his battery in his Audi and it caused the auto/ tiptronic gearbox to malfunction and only automatically go to second gear, although he could drive manually in all gears. The result was it had to go onto a computer and be completely re-programed, £146 sir, all labour thank you very much, MB and VW tiptronic owners beware!

Don't know about our motorhome, don't believe ours has one but my car has and the only procedure when disconnecting the battery is to ensure that the negative is removed before the positive and that the inital removal is done with a 'clean' break so not to make a spark as this can damage the ECU's and that it is not reconnected for at least five minutes.

On reconnection, which again must be done 'clean' all the ECU's are in an as new state and have to all be 're-programed' or 're-trained' e.g. the window lifts have to have their travel set by fully moving them down and holding the button for five seconds then up and holding the button for five seconds. The vehicle engine, gearbox, body and suspension ECU's then learn how you drive over a period of time.

 

Bas

[myspeak]

Of course the technology is there to provide an automatic retention to a

back-up battery but an auto-electronics-pro told me it is not (yet) used because "generally it is not a problem". It will probably be standard in the near future. Another aspect of all this electronic black magic in modern cars

is that a typical new vehicle has on average 15-20 individual micro-chips all doing different jobs and frequently problems arise when they have to communicate with each other, or problems arise because one chip inadvertently interferes with or even overrides one of the other chips, maybe only rarely and via one logical path only, maybe communicating with another chip where it has no business - it is all terribly complicated and as a former freelance software consultant of 15 years it is no wonder that problems arise from time to time: You simply cannot "desk-check" all the possible combinations

of individual logical paths that might be active at any given moment, nor predict the exact sequence of events in such a complex interplay, it would take years if not decades, and it just isn't done, and when all these systems are released on the market there remains a certain sector of "crossing your fingers", how big that sector is I don't know and it would be difficult to find someone free enough and/or honest enough to tell us. Reassuringly, the same is the case for real-time automated flight systems for everything from the new Airbus Super Jumbo over the Space Shuttle to ICBMs!!

 

All this gadgetry is of course very impressive and elegant, and some of it even useful when it works, but for any motorcaravan my guideline would be: The further off the beaten track you wish to go, the less of all that nonsense, it is certain to catch up with you some day and let you down in a big and probably expensive way.

 

It is partly for these reasons that my motorhome is a 1976 MB508D.....

I did look at brand new Sprinter- and Ducato-based ones but decided against them, mainly on grounds of complexity and possibly reliability

compared with the 508D - which only cost me 4,500 Euros and I have spent another 3,000 E, so for 7,500 E I have a rugged and reliable truck which will keep driving longer than I will!

[myspeak]

I have just uploaded a picture of my old truck - let us see if THIS technology works: Do we see a picture??

 

No it didn't show up! Typical!

 

Try clicking here then:

http://forums.outandaboutlive.co.uk/forums/profile/get-photo.asp?memberid=1872&type=photo

[Terrytraveller]

Thanks to everyone who contributed to my enquiry. We have had 158 views so far and five positive experiences reported, the other 154 viewing probably haven’t disconnected their battery yet.

 

Out of five battery disconnections, two caused no problem and three required some ECU re-training.

 

Hopefully we will receive more input as time goes by. Actual personal experiences of any problems or better still NO problems after battery disconnect and reconnection, will be very welcome, giving make, year, model and engine size will also be useful.

 

Regards Terry

 

[Guest peter]

Of course the secret is, to connect up a small 12V battery to the leads before you take off your battery. That way you don't lose anything, radio code etc.

[Terrytraveller]

Hi Peter,

 

Good idea in theory, but would that not mean you will have un-insulated clamps threshing about under the bonnet as you wrestled with removing the old battery? I think we have established that connecting and disconnecting the battery, will likely cause arcing which the ECU perhaps wouldn’t be pleased with.

 

Also connecting batteries with unequal resident charge, we assume the old battery is nearly dead, would cause a surge between the charged and discharged battery.

 

Keep the ideas coming Peter and thanks once again for your input.

 

Regards Terry

 

[Brambles]

Terry, I have 2003 ducato 2.0 JTD (same as yours), and have disconnected the battery twice with no problems at all. on first occassion the radio lost it's coding. The 2nd time the radio did not lose it's code. The difference being the length of time I had the battery disconnected. The 2nd time just being a few minutes.

 

Someone mentioned negative connection should be removed 1st. Some will say its because of hydrogen gas collecting around the +ve terninal, but forget all that it is very simple why. Think of your spanner accidently shorting to the chassis, very easily done. Do the negative first and your spanner will not act as a short to the chassis if you slip.

 

Jon.

[Terrytraveller]

Hi Jon,

 

Thanks for the positive input so we can now say ;-

 

Out of six battery disconnections, three caused no problem and three required some ECU re-training.

 

Regarding your advice about disconnecting the battery, negative ground first and securing the lead away from the battery, I wholeheartedly agree with that procedure.

 

Regards Terry

[Brian Kirby]

Terry

This is an excellent thread, for which thanks.  Myspeak's comments were relevant to a Mercedes Vito vehicle.  Others generally haven't stated which vehicles were the subject of their posts and, perhaps more importantly, which versions/years.  Without that additional details the comments are robbed of much of their value, so I wonder if I might eneter a plea for full base vehicle details to be appended to all posts on this subject. 

Because this technology is still fairly new and changes relatively quickly, I think we need make, engine variant and year to know roughly where the problems might lie.

For example, there is no guarantee that a Fiat 1.9JTD will have the same electronics package as at Peugeot 1.9, a Citroen 1.9 (all from the same factory) or, for that matter, a Fiat 2.3 or 2.8JTD.

It also seems extremely improbable that the rules for disconnecting the starter battery on any one make of van, will translate to other makes.  What works for Fiat may well be damaging to any/all of Peugeot, Citroen, Renault, Iveco, Ford, Volkswagen or Mercedes, irrespective of their years of manufacture or engine variant.

As with so many things tecchy, I suspect the devil will lie very firmly in among the details!

[Bill]

myspeak - 2007-02-28 6:29 PM

 

 

 

for any motorcaravan my guideline would be: The further off the beaten track you wish to go, the less of all that nonsense, it is certain to catch up with you some day and let you down in a big and probably expensive way.

 

It is partly for these reasons that my motorhome is a 1976 MB508D.....

I did look at brand new Sprinter- and Ducato-based ones but decided against them, mainly on grounds of complexity and possibly reliability

compared with the 508D.....

 

I have a rugged and reliable truck which will keep driving longer than I will!

 

I agree fervently with every word you say. When I bought a "new van" which was an F-reg "notch-front" Merc my nearest and dearest went ballistic, but I am quite sure we are right and she is wrong.

 

 

[myspeak]

Hello All,

1. For the record, my friend's MB Vito, which I described in the Morocco thread, is from 2004, with the biggest engine (156HP?) and ALL factory fitted options and extras, beautiful vehicle and it would outperform the Golf GTI I used to drive in the UK in the 70s, but it is FAR too complicated,

in my view most of this electronic black magic should be kept well away from motor vehicles.

 

2. Peter, I could not resist copying that lovely bouncy-blonde-girl, so I have my very own now.

 

3. Bill, thanks for your comments - which MB have you got then?

Any pictures to show us? So far I only have the one of mine, more to follow when I get back on the road.

[Terrytraveller]

Hi Brian,

Thanks for your support and interest, the subject has now become topical because of fuel problems up & down the country effecting the ECU/ECM, a failing sensor causing a limp home mode to be initiated by a faulty and contaminated sensor.

 

I have a Peugeot manual on disk bought from Ebay, some of the hints would certainly be useful to owners who work on their vehicles.

 

For example – battery arcing could cause the Air bags to activate, so there should be no one in the vehicle while connecting and disconnecting the battery.

 

After disconnecting the battery, the airbag pyrotechnics can activate for up to 30 minutes afterwards, as the SRS system modules have their own power supply, by the way of capacitors, which take time to discharge.

 

Fast chargers are not recommended as they can damage the ECU, anything taking the battery to 16 volts is curtains for the ECU the manual states.

 

Although we have 260 views, only a few have reported disconnecting the battery.

 

Electrical signals from the fuel and ignition system sensors are received and processed by the electronic circuits in the ECM

 

Functions - Outputs from the ECM control the following:

 

Injectors - by controlling the length of time each injector valve remains open.

Fuel pump relay.

Idle speed control system.

Evaporative emissions system.

Exhaust gas re-circulation.

Ignition timing and knock sensing.

Self-diagnosis of faults, indicated by an LED on the ECM or a MIL or check engine warning light on the instrument panel (some models).

Emergency `limp-home' programme, which substitutes an average value for any failed sensor enabling the vehicle to be driven to a workshop for correction.

 

Regards Terry

 

 

[icelander]

Did I see a thingy that you plug into the cigarette lighter while you disconnect a battery - could be machine mart or screwfix

[icelander]

hi Bill

 

Having purchased in 1999 a 1999 300tdi Land Rover Van on grounds of relaibility instead of the latest TD5`s all siging all dancing bmw engined thing. Later when in Iceland I spotted a TD5 being towed back to the ferry by a old Landy

 

Nuff said?

[Terrytraveller]

Hi Rob,

 

Just sent you a PM re-Skype.

 

Re 'Cigar lighter' memory saver, Peter thought of that earlier. My thoughts on that are, with a memory saver in the cigar lighter supplying power to Radio and the ECU keeps saftey restraints alive as well, and remember the ignition must be switched on for most cigar lighters to be operative, the ECU and explosives in all the SRS devices will remain active. You will still get arching as the battery is disconnecting, probably more so as both vehicle battery and battery saver try to balance their charge with each other.

 

Its very unlikely the SRS components will activate even if a sharp blow is delivered to the vehicle, but then I didn't think the labour party would be in power for so long!

 

Regards Terry

 

 

 

 

[BrianR]

My 'van is powered by a 1996 Peugeot 2.5TD. I have changed the battery on it twice, with no problems - probably because it is relatively unsophisticated.

 

Brian

[tonyishuk]

Fiat 2002 2.8 JTD. Disconnected the battery for connecting a maintence charger ( Halfords £18). Reconnected with no problems..

 

Rgds

 

[Terrytraveller]

Thanks Brian and Tony for your input, it seems the account now stands at :-

 

Out of eight battery disconnections, five caused no problem and three required some ECU re-training.

 

Some operators removed the battery connections more than once, removing the leads for charging the vehicle battery.

 

Regards Terry

 

[Dave Newell]

As a slight aside, sometimes it can be beneficial to disconnect the battery to let the volatile memory clear. My father runs a '92 Peugeot petrol car with electronic fuel injection. Because he doesn't very often do journeys of more than a couple of miles the car was quite poor on fuel consumption. We disconnected the battery, after leaving it all switched off for 5 minutes to shut everything down, and left it overnight. We reconnected it the next morning and immediately took it for a 20 mile journey on fast dual carriageway at constant cruising speed. Result was the engine management "re-learnt" a new set of conditions and the fuel consumption was restored. He now does this about once a year when the fuel consumption goes off.

 

It should give a written instruction of the procedure for disconnecting the battery (and re-connecting) in the owners handbook.

 

D.