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Old 13th February 2014, 21:52   #46
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

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Originally Posted by ridinthru' View Post
Folks,

My brother's Chevy Spark met with an accident some months ago and has been with the service centre for more than 2 months (reason being the ECU was also damaged and needed to be replaced, but a replacement was not available) The part was to arrive from Bangalore (God knows why !) and since it's been so long, they've come with an alternate solution - get another car's ECU, clean swipe it, reload all relevant software and install it in the Chevy..!!
We are confused that should we agree to this arrangement, specially since the car's been in the service centre for more than 2 months due to un availability of replacement ECU ?

Woud appreciate some insight on this..

Cheers !

RD
I don't have experience with your particular car, but I can give you a few pointers.

I'm very surprised that the ECU got damaged in an accident. It is possible, but it is very rare indeed. Would be interesting to hear how they figure out the ECU is at fault and not something else. It's much more likely in an accident that sensors and or the wiring harness gets damaged and that could/would throw a whole host of different codes.

Going back to your original question; yes, that is entirely possible. But you need to have the whole procedure done by somebody who really knows what he/she is doing. It's all down to hardware/software/platform and maintenance release and which ones you can combine or not.

For instance, swapping an ECU on my Jaguar is a real Royal Pain. Even, when you have a brand new one, let alone when you start with one from another car.
Sometimes, other electronic modules might need swapping and or updating as well to remain compatible with the new ECU.

So, again it can be done. On the upside. It will be very obvious if it was done properly or not. I'd say either everything will work perfectly or you will have a whole host of problems. You are very unlikely to end up with a few things that don't work well.

Sorry I can't be more specific. But this is an area where you really need to have real knowledge/experience and access to the right procedures. But that might be equally true for installing a brand new ECU.

Jeroen
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Old 14th February 2014, 14:09   #47
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

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Originally Posted by ridinthru' View Post
... My brother's Chevy Spark met with an accident some months ago and has been with the service centre for more than 2 months (reason being the ECU was also damaged and needed to be replaced, but a replacement was not available) The part was to arrive from Bangalore (God knows why !) and since it's been so long, they've come with an alternate solution - get another car's ECU, clean swipe it, reload all relevant software and install it in the Chevy..!! ...
1. Have they shown the damaged ECU to you?

2. Waiting that long to get a replacement ECU from Bangalore sounds odd, considering it is a standard part and should be in stock. Even if they have to get it from Gujarat, it will take max. 10 days

3. There is nothing to 'wipe clean' other than Error Codes. There isn't any last moment loading of software required - this is not a home or office 'computer' - when one instals an ECU, even if from another car. At the most some calibration needs to be done, that's all. It is OK to get an old ECU from another car, but it would be better to get a new ECU as replacement - there wouldn't be any warranty on the old ECU!

All in all, their expressions and explanations sound fishy. Perhaps someone should go there and check what is happening, instead of accepting their statements.
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Old 14th February 2014, 14:58   #48
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

Thanks Jeroen & DerAlte ! I should have mentioned that the accident happened in Varanasi and the car is at the Chevrolet dealer there. My brother is there looking into things and he did mention (in fact he sent me snaps of the car post the accident and the ECU was damaged.. read broke apart..). Since the repairs are being done under valid insurance claim, our point is that we are not sure if this alternate ECU solution would work flawless, and also the fact that this would not be paid for by the insurance company, since it's a second hand part being arranged by the service centre there..
Should we bear the expenses and go ahead with the repairs..?
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Old 14th February 2014, 23:22   #49
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

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Originally Posted by ridinthru' View Post
Thanks Jeroen & DerAlte ! I should have mentioned that the accident happened in Varanasi and the car is at the Chevrolet dealer there. My brother is there looking into things and he did mention (in fact he sent me snaps of the car post the accident and the ECU was damaged.. read broke apart..). Since the repairs are being done under valid insurance claim, our point is that we are not sure if this alternate ECU solution would work flawless, and also the fact that this would not be paid for by the insurance company, since it's a second hand part being arranged by the service centre there..
Should we bear the expenses and go ahead with the repairs..?
DerAlte is much more experience with what ECU's are here on the Indian market, so it will be straightforward. Hell, on my Alfa with the Bosch L-tronic system you can just swap the ECU, no clearing of codes is necessary or even possible! Real plug and play stuff. But on the Jag and Lexus its a real nightmare.

By and large, the more complex (often high end) cars also get more complex when it gets to swapping electronic parts.

Jeroen
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Old 16th February 2014, 08:54   #50
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Originally Posted by DerAlte View Post
3. There is nothing to 'wipe clean' other than Error Codes. There isn't any last moment loading of software required - this is not a home or office 'computer' - when one instals an ECU, even if from another car. At the most some calibration needs to be done, that's all. It is OK to get an old ECU from another car, but it would be better to get a new ECU as replacement - there wouldn't be any warranty on the old ECU!
So you say that the basic software on any stock ECU are the same and if needed on emergency can be added?

What about fueling and timing which will be different for cars available?

Curious to learn. Thanks.

Anurag.
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Old 16th February 2014, 18:08   #51
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

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If the service center you visit is an authorized one, it should have the Service Manual.
Yes, looks like your service center has cleared the DTC.
If the DTC comes back, then they'll need to systematically go through the procedure mentioned in the Service Manual.
Yes, it was an authorized service center (Qutab Auto in Gurgaon).

The light came back with some problem starting up the engine for the first time. I drove for a day or two and now the light is gone!

Shall I again wait and watch?
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Old 17th February 2014, 12:31   #52
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

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Originally Posted by ridinthru' View Post
... Since the repairs are being done under valid insurance claim, our point is that we are not sure if this alternate ECU solution would work flawless, and also the fact that this would not be paid for by the insurance company, since it's a second hand part being arranged by the service centre there..
Should we bear the expenses and go ahead with the repairs..?
Why wouldn't the insurance pay? Simple logic: the car will not work without the Engine ECU, hence it is not a peripheral part - it is an integral part with no natural degradation like plastic and rubber items. Please ask them again.

IMHO you should avoid using an ECU from another (possibly totalled) car. Get a new one - avoid surprises that may accompany an old one.

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Originally Posted by Jeroen View Post
... on my Alfa with the Bosch L-tronic system you can just swap the ECU, no clearing of codes is necessary or even possible! Real plug and play stuff. But on the Jag and Lexus its a real nightmare.
...
L-Jetronic, I think. And no, even on the Jag and Lexus this part will be a drop-in replacement, followed by calibration and fine-tuning.

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Originally Posted by a4anurag View Post
So you say that the basic software on any stock ECU are the same and if needed on emergency can be added? ...
For *one* specific engine - yes, *all* the software will be the same. Doesn't need any post-installation software modification - that is why it is called 'firmware', not 'software'. Updates, I presume, would have been applied before the ECU is delivered for installation.

Didn't understand the expression I have marked in bold-u/l. What 'emergency'?

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Originally Posted by a4anurag View Post
... What about fueling and timing which will be different for cars available? ...
Your question is a bit ambiguous!

If you mean one specific car / engine model, injection and timing do not vary significantly between other instances of the same, even if manufactured 1 year apart. The differences, to put it simply, are mechanical tolerances - and these are very tightly controlled while manufacturing parts. That is why ECU can be a drop-in replacement, since the minor variations in tolerances are reckoned with.

If you mean 'different cars and models' - the software may be the same or it may be different. That depends on significant criteria. For example, Renault Duster has an 85PS variant engine and a 110PS variant. The engine is mechanically the same. What is different between the 2 variants are the 'maps' - injection and driveability (even the gearboxes are different). The same 85PS engine (and gearbox) does duty under the Nissan Sunny bonnet. The MJD engines used by different manufacturers have the same firmware in the ECU, but may have slightly different maps.

Some car manufacturers use slightly different firmware complement in cars of their normal and luxury lines - everything else remaining the same. Other than these, ECUs used by different car manufacturers (also, ECUs manufactured by different injection system manufacturers) are have different hardware and software. So, one can't use a Delphi ECU in place of a Denso one - that would need extensive tests on a test bench. I am assuming both can use the same sensors and actuators, which itself is tenuous assumption.
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Old 17th February 2014, 13:28   #53
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

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Originally Posted by DerAlte View Post

L-Jetronic, I think. And no, even on the Jag and Lexus this part will be a drop-in replacement, followed by calibration and fine-tuning.

So, one can't use a Delphi ECU in place of a Denso one - that would need extensive tests on a test bench. I am assuming both can use the same sensors and actuators, which itself is tenuous assumption.
Yes, correct its the L-Jetronic on SerieIII, later models (Serie IV) had the slightly more advanced Motronic system also found in many MBs of that era.

Mechanically speaking just dropping an ECU into a Jag is possible. Getting the engine up and running with it might be something different alltogether. Before you can do that you need to do a lot of home work. The isssue with the Jag is that they come with a whole host of other computers, the ECU just being one of them.

Ever wondered why on Jaguar X308 so few engines get swapped by DIY mechanics? This is the reason, getting the engine out and a new one in is pretty straightforward. Getting the engine up and running with the electronics is a whole other matter.

The first thing you run into is the securtiy immobilizerset up. You need a special analyzer to get passed that. I have a very eloborate OBD Jaguar specific analyeser on my laptop, but without the dealer I could not do this.

Because of the various computers (e.g. body control module, instrument cluster module etc) you need to ensue that each and every moduel has the correct revision level to the will be able to communicate to each other. If not, you do have to get the revision levels adjusted. So, these computers are proper computers, both from a Hardware and Software perspective. And they come with all the associated headaches of matching revision levels and backwards incompatibility often associated with computers.

A competent mechanic will know the exact procedure and he will also know how to order an ECU that will simply "drop in". He would still need to hook it up to an analyzer to get passed the security immobilizer set up. If he can't get the ECU with the correct revision levels, he should be able to know which unit to order and how to correct.

Then there is the calibration and fine tuning. What that entails is very much make/type specific. Not so much software loading as just settting parameters.

Again, the above is just my experience with the Jaguar XJR.

So, dropping the ECU in, mechanically speaking, tends to be very easy. Getting it up and running, depending on make/model can be a bit more complex and could take several hours, provided you have the correct tools/analysers and competence.

To your last point, ECU's of different brands being able to use different sensors/actuators. Like yourself, I would like to think so, but I'm not so sure in practice. I really don't know how much standardisation is applied to this part of the automotive industry? I can imagine there are sensors that are very brand/model specific? Even if not the sensor itself, the housing in which it often comes is certainly brand/model specific.

Jeroen
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Old 17th February 2014, 17:01   #54
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

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Originally Posted by Jeroen View Post
... The first thing you run into is the securtiy immobilizerset up. ...
That is the only hurdle in getting the engine to run! But then, the engine ECU needs only a permittance from the immobilizer. If one assumes that the immobilizer is in 'go ahead' state (all security checks passed), the engine ECU will not query the immobilizer again - till there is a reset recycling.

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Originally Posted by Jeroen View Post
... Because of the various computers (e.g. body control module, instrument cluster module etc) you need to ensue that each and every moduel has the correct revision level to the will be able to communicate to each other. ...
All of these units are 'slave' to the engine ECU, and wouldn't hold the engine operation to ransom. 'Communication' is not 'Revision'-dependent - it wasn't in 'Windows category of software engineering horrors! The snafu was 'what' was being communicated, not 'how'.

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Originally Posted by Jeroen View Post
... A competent mechanic will know the exact procedure and he will also know how to order an ECU that will simply "drop in". ...
Urban folklore!

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Originally Posted by Jeroen View Post
... Then there is the calibration and fine tuning. What that entails is very much make/type specific. Not so much software loading as just settting parameters. ...
It wasn't that esoteric an activity - the default parameter set was good enough to get one going. Different matter altogether if one is trying to shave fractions of seconds off 0-60 times. That mechanics created the folklore is also legion - who will pay them otherwise? Automotive software engineering in UK was never that bad as it is made out to be.

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Originally Posted by Jeroen View Post
... So, dropping the ECU in, mechanically speaking, tends to be very easy. Getting it up and running, depending on make/model can be a bit more complex and could take several hours, provided you have the correct tools/analysers and competence. ...
Seldom needed to be done nowadays (failure rates are down manifold) - but it usually takes less than 30 minutes with the checklist.

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Originally Posted by Jeroen View Post
... I really don't know how much standardisation is applied to this part of the automotive industry? I can imagine there are sensors that are very brand/model specific? Even if not the sensor itself, the housing in which it often comes is certainly brand/model specific. ...
The electrical interfaces to ECUs are pretty much standard (the technology is a few decades old for most of them). So are the mechanical / mounting interfaces. Minor difference in characteristics between different sensor / actuator vendors, mostly physical sensing / actuation range. Housings don't matter (and they are not car brand/model specific, they are vendor specific). It is the harness connector that matters the most - they are car brand specific.
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Old 17th February 2014, 19:42   #55
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

Urban folklore? Well, I wouldn't argue that when it comes to electronics there are a fair numbers of myths floating around the world, the internet and this forum too.

But in my case, I tend to talk about my own hands-on experience. Being a Jaguar owner that does this sort of stuff himself. I was a member of one of the affiliate clubs of the Jaguar Clubs of North America. I was on their board and two of our board members were employees of Jaguar. One was the head of Spare Part department, the other one Head of the Service Department. One of our other members ran a independent company servicing and refurbishing electronic PCB, including some car stuff.

So, between the four of us we had pretty good understanding and access to just about any bit of documentation, procedure and tooling. We could trouble shoot down to component level in the various modules. Whenever members had problems with their electronics we tried to help out. So I've swapped a number of ECU's and other modules. And rarely was it as straight forward as advertised, so to speak.

Rule of thumb on this stuff was as follows:

Any piece of electronics post-dated to the introduction of the XJ(R), i.e. X300/308 was pretty basic and all more or less plug and play. (like the Spider, you can't even adjust anything if you want, save for putting a new EPROM on it.

Anything just out of the factory, say less than 12-24 months tended to be pretty straightforward as well. Usually, with a bit of luck, plug and play and a bit of fiddling on the old OBD fancy Jaguar analyzer.

The problems started with anything a bit older and anything over 10 years old, e.g. X300/X308 there were always issues. When you start swapping modules, inserting a brand new one, into an old car, with old wiring/harnesses and old electronics you might see all sort of niggling issues, at least a whole bunch of U-codes (http://www.obd-codes.com/trouble_cod...work-codes.php) thrown at you. Then you need to get down to the actual bus and look at signals to figure out what is happening. Even well trained Jaguar Mechanics usually can't do that. Its just beyond what they are trained on.

Maybe its Jaguar specific, but their wiring harnesses are pretty pathetic, quality wise. You start messing with the ECU or any module, you upset the harness and you might find yourself in troubled water.

On the sensors, I agree the connectors are a pain. But then, I always felt that all connectors used in the auto industry were/are designed by a bunch of retards. So as long as I know which wire goes where I'm happy to just solder them together. Honestly, a lot of these connectors are really badly designed and I just don't understand they can't do better. If you have an O2 sensors with a connector dangling underneath the car, would it not be a good idea to have that connector waterproofed? Most car manufacturers haven't figured out the concept of water proofing electrical connectors.

Also, if you order from Jaguar say a "solar light sensor", you will get the sensor plus the associated bits and piece of the top of the dashboard. That will not fit in a Jaguar. Even if you strip it to the actual (Denso) sensor, I'm not sure that sensor will fit into say a BMW. Be it mechanically or electrically. Maybe it does, I just don't know.

Finally, I don't know if this is Jaguar or USA specific possibly both, but the actual time it took to replace say that solar light sensor is about five minutes. That would include the mechanic walking up to the spare part supervisor and getting his part. But he would probably spend 20 minutes all together on filling out all the necessary paperwork. Jaguar had specific times allocated for each and every repair job, but I could never figure out if they included the form filling time as well. My two fellow board members tended to be a bit elusive on this. Usually, when I started asking pointy questions about this, they would try and change the subject, along the lines, don't you worry about that. Here we are just enjoying our hobby, which was true. Still wondering though….

Although I'm all for quality work, sometimes I just yearn for the day when I pulled up at a petrol station and the guy would open the hood, check and fill oil, cooling water, brake fluid and screen wash water. Of course these days, it takes a half day course just to figure out how to open the damn hood. Let alone trying to establish what type of oil/cooling liquid etc needs adding. They call it progress I think. Everybody needs to be an expert, I don't think so.

On this master/slave thing: If your transmission module isn't talking to your ECU or doesn't understand what its saying you're not going anywhere. You might be able to start, but that is as far as it goes. I've swapped an ECU on a XK8 and the body module would not communicate properly, couldn't even get the engine to start. We had to get a new ECU, well actually an older model, before it worked properly.

So bottom line: Fiddling with electronics isn't everybody's cup of tea. As long as everything goes as per the standard procedure, things will be fine. When it doesn't you're in deep s**t and there aren't that many mechanics that will know what to do. That's in Europe and the USA, maybe its different in India, I just don't know, I have no relevant experience.

Jeroen

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Old 18th February 2014, 07:09   #56
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

Just to add to the above; Just found this somewhere on my Hard Disk. Below a little article I wrote for the Jaguar magazine, soon after I had joined them. The world over, car enthusiast struggle with electronics. And the more classic owners often believe that electronics in cars are going be the death for the true classic car enthusiast. As per some of my other posts on this forum, I disagree.

Quote:
As some of you know, Frances and I moved from the Netherlands to Kansas City some time ago. I got myself a very nice 2003 XJR the second day I arrived in the US, joined the Club and the rest is history as they say.

Back in the Netherlands I still own two classics, both in storage; a 1986 Alfa Romeo Spider and a 1982 Mercedes W123 200. I’ve been active in both clubs.

It’s interesting to see that some of the discussions on classic cars are just about identical on both sides of the pond so to speak. For instance, when does a car become a “classic”. If it is only it’s age, then the general consensus seems to be that anything over 25 years, regardless of make, type or appearance is regarded a ‘classic’. Except that is for Mercedes. I can still walk into any Mercedes dealer in Europe and get parts for my 1982 car.

Anything up to 30 years old is still regarded by Mercedes as a “daily drive” and you can walk into any Mercedes dealer in Europe and get any part.

Whereas if you buy an Alfa Romeo brand new, you’d be lucky to get any spare parts from your Alfa Romeo dealer as soon as the warranty period is over. It’s not unknown for Alfa Romeo to run out of spare parts during the warranty period. This is the brand that will be relaunched in the US in 2014. I don’t think they stand a chance with the US audience at large.

Anyway, one other very common topic of discussion amongst classic car enthusiasts on both sides of the pond is the future of classic cars in general. There is one distinct difference between Europe and the US. In Europe the environment is a much bigger theme than here in the US. So for instance, in various European major towns you’re simply not allowed to take classic/old cars into the city because of regulations on emissions. Not much I can do or say about that, other than I’m not a member of any of the green parties pushing this political agenda. I own four classic cars, love flying and hope to own a big 1000HP motor yacht sometime. If anything my CO2 footprint puts me right of Atilla the Hun, or so my more liberal friends back in Europe want me to believe. But hey, I can’t take people who eat whole grain bread for environmental reasons seriously.

On a more serious note: There is a school of thought that believes that as cars get more complicated it will be impossible to get them serviced or service them ourselves as the cars get older. In particular people tend to refer to the electronics of modern cars.

I don’t subscribe to this theory at all. Let me explain; Firstly, it is very rare for electronics to break down. Just visit the various forums. For instance, take my 2003, X308. Various forums and the majority of the topics is very similar as what you will find on forums on the very first XJ series. It’s about rust, replacing shocks, bushings, engine problems, how to replace a wiper, which sparks plugs to use, how to change the thermostat, how often to change oil filters etc.

Admittedly, you will find a number of postings on these forum relating to what seems to be “electronics”. However, based on my own experience, I’d say it is very rare for the electronics to go wonky. Most of the so-called “Electronic Problems” have a mechanical or electrical root cause. A sensor that doesn’t work, a connector with too high resistance, a break in a cable, a ground problem, a blown fuse etc. (my X308 has more than 600 fuses so go figure!)

Now, it does take different skills/experience to trouble shoot these sort of problems. Also, you need different tools. Like for instance a simple OBDII scanner. For less than
$ 60,-- you can get yourself an OBDII scanner that will allow you to read the various malfunction codes and reset the Check Engine light! Fixing your classic will never be the same! You don’t need to open the hood and break out the tool kit. Just hook up the scanner! No dirty finger nails anymore!

I’ve had some problems with my X308. Managed to diagnose all of them myself, but just to be sure I went over to my friendly local Jaguar dealer to get it hooked up to their diagnostic tool suite, which on every occasion confirmed my own findings. But at a hefty price! They’re very friendly, but not cheap. So I’ve taken the plunge and bought myself a complete Jaguar Software package including all Enhanced Jaguar functions. Not sure what that means, but the enhanced package doubled the price, so it must be pretty cool!

When my new fancy Software package arrived I was anxious to put it to some good use. Unfortunately, my XJR was running fine. Luckily, Ron Hendersson owns any number of Jaguars with all sorts of problems. Sure enough, Ron had a XJR with plenty of “electronic” problems, so I hooked it up to my laptop, ran my fancy Jaguar Enhanced Software and within 15 minutes we were able to isolate the problem to the mass air flow meter. Cleaned it thoroughly and now the XJR runs fine!

So, I’m not too worried about the future of classic cars. Even if they come packed with computers. Modern cars, with all their electronic gadgetry will become classics. I’m sure when there’s a market, there will be specialists who will rise to the occasion, offering services or tools. Let’s take Bosch for instance. They have a special division where you can get all of your classic Bosch electronics overhauled. My Alfa Spider has a Bosch L-Jetronic and the Mercedes W123 were fitted with K-Motronic Bosch system. I can get any part from Bosch or have them service all of my electronics.

On my XJR, already here in the US there are several electronic specialists advertising on the Internet claiming they can repair any Jaguar ECU you can throw at them!

The software I bought was still a hefty $500,--. But five years ago, the identical package would retail at more than $ 5,000,--. So diagnosing and fixing electronic problems on a modern classic becomes more and more affordable.
So the (electronic) classic future looks bright!
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Old 18th February 2014, 11:41   #57
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

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Originally Posted by Jeroen View Post
... Honestly, a lot of these connectors are really badly designed and I just don't understand they can't do better. If you have an O2 sensors with a connector dangling underneath the car, would it not be a good idea to have that connector waterproofed? Most car manufacturers haven't figured out the concept of water proofing electrical connectors. ...
Cost pressure! They definitely know it, as water-proof connectors have been around for >30 years now. Sometimes costing / economics demands that engineers use the cheapest available stuff and then pray! There is no law governing choice of components, insurance takes care of liability and (hopefully) the poor sod who bought the car will get on with life!

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... My two fellow board members tended to be a bit elusive on this. Usually, when I started asking pointy questions about this, they would try and change the subject, ...
Heh heh obviously. Workers' compensation rules trump any attempt at stopwatch-toting industrial engineering!!!

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Originally Posted by Jeroen View Post
... On this master/slave thing: If your transmission module isn't talking to your ECU or doesn't understand what its saying you're not going anywhere. You might be able to start, but that is as far as it goes. I've swapped an ECU on a XK8 and the body module would not communicate properly, couldn't even get the engine to start. ...
Well, there is very little inter-dependency actually - unless safety interlocks have been built, like 'car should be in neutral for engine to start' or 'clutch should be depressed before starter motor is allowed to tick over'. Otherwise, the simple rudimentary communications is at least
(Transmission to engine):
- calculated Road speed (after reckoning with all ratios till tyre surface),
- Currently engaged gear and
- With auto boxes, 'Please reduce engine RPM to that suitable for a shift' (and its complement 'I am done shifting - go back to Driver Demand), and
(Engine to transmission):
- 'Speed reduced!' (Auto boxes)
- (In some cars) 'Oy, I am lugging, please downshift'

There are others in more modern cars, such as Hill Climb Assist (ascent, descent) etc.

By default, missing or not understandable input makes ECUs to default to safe substitute values, preventing mal/dysfunction. What might suffer at most is 'smoothness' and/or driveability - it will still work.

Last edited by DerAlte : 18th February 2014 at 11:45.
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Old 19th February 2014, 19:11   #58
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Post Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

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Originally Posted by heysac View Post
Yes, it was an authorized service center (Qutab Auto in Gurgaon).
The light came back with some problem starting up the engine for the first time.
I drove for a day or two and now the light is gone!
Shall I again wait and watch ?
Hi HeySac, based on the DTC description in the Service Manual, it appears that this DTC is triggered when the delay between the throttle butterfly being commanded to a particular position by the ECU & it actually getting there is greater than the expected value. As the DTC description says, this delay is checked once per Driving Cycle - possibly when the ignition is turned ON.

Since it appears that this error could cause your car from being started, your best option is to get it checked at your local Maruti Authorized Service Station. Ideally, they should have the Service Manual for your car & hence be able to walk through the diagnostic procedure step-by-step.

There is mention of "Calibration" of the throttle body prior to carrying out the diagnostic process. According to the manual, this basically involves turning ON the ignition for a minute, & then turning it OFF for a minute.
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Old 19th February 2014, 19:19   #59
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

Quote:
Originally Posted by im_srini View Post
Hi HeySac, based on the DTC description in the Service Manual, it appears that this DTC is triggered when the delay between the throttle butterfly being commanded to a particular position by the ECU & it actually getting there is greater than the expected value. As the DTC description says, this delay is checked once per Driving Cycle - possibly when the ignition is turned ON.

Since it appears that this error could cause your car from being started, your best option is to get it checked at your local Maruti Authorized Service Station. Ideally, they should have the Service Manual for your car & hence be able to walk through the diagnostic procedure step-by-step.

There is mention of "Calibration" of the throttle body prior to carrying out the diagnostic process. According to the manual, this basically involves turning ON the ignition for a minute, & then turning it OFF for a minute.
Thanks! The light has been gone since the last 4-5 days and all looks fine. As you mentioned, when the light comes on for the first time, there is a problem starting the car. The way out is to take the key out and then start it. I will visit the MASS for a thorough check-up if the light ever comes up again.
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Old 8th March 2014, 23:22   #60
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Default Re: TechSpec® : Understanding On-Board Diagnostics, also known as ECU, ECM, EMS

Hi,

I need some help here. I have purchased a 2006 Palio 1.6 Sports.
The engine check lamp doesn't come on when the ignition is turned on.
Got this checked with a Fiat mech, and he says nothing to worry as there is no problem with acceleration or there is no missing. The car runs just fine.

My worry is will this bring up any issues later?

Regards,
Alex
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