ECU failure?

[Stuhart]

I have a 2009 ML63 AMG which I bought a few months ago and from almost day 1 I've been having problems. They started with the car failing to crank and appearing to be stuck in Park though the battery and all other electrics were working fine. Independent Merc garage mechanic (here in Qatar) diagnosed it as a faulty Intelligent Servo Module and replaced it at great expense. Almost immediately on its return it suffered the same issue again. Identical symptoms though the mechanic maintained it was a separate issue from the previous one and said this time it was an issue with the ignition barrel so the internals were also replaced at further expense. And guess what? Shortly after this it failed to start again! Identical symptoms once more. Now the mechanic is saying it's the ECU so I'll need a new of those too. To say I'm skeptical is putting it mildly. It may well be true but then I'm thinking was this the problem all along and the previous "fixes" were unnecessary? However, what I have discovered now is if I disconnect and reconnect the battery it would appear to reset itself and allows it to start so I'm doing this every morning to get it going and living with it like this for the time being while I decide if I really want to throw another sack of cash at a problem I'm not convinced is being properly diagnosed. Does anybody have any experience or an opinion on this?

 

[Botus]

both issues u had fixed are normal Mercedes issues. But it sounds like the place u went to are guessing rather than diagnosing

the ecu might be faulty (as modern electronics don't last long) particularly if its been molested to tune it up, but I wouldn't expect its your issue

 

[LostKiwi]

Get yourself an MB specific diagnostic kit (£70-200 depending what you go for) and read the ECU looking for any fault codes. Disconnecting the battery suggests there is a fault code that's getting cleared. If there is a code resetting via diags is always preferable to disconnecting the battery and risking a surge destroying an ECU somewhere.

 

[alexanderfoti]

What happens during a failure to crank.

Insert key, turn to start then what?

 

[mioba]

ML63 are disposable in Quatr,

Seems your indy is cluless, has he even read codes, did you see, he has no clue by the sounds of it - sorry but i would be fuming.

 

[Stuhart]

What happens during a failure to crank.

Insert key, turn to start then what?

Then approximately nothing. Electrics come to life but a turn of the key results in nothing at all. No electronic pings or sounds of solenoids or pumps or servos or anything. Just silence. Though just as strange is that at times when it's remembered who it is and has started without the battery needing to be disconnected (the longer you leave it the more likely it is not to start) it has more often than not ran for a number of seconds and then the dashboard goes crazy and just about every warning light comes on. At that point I turn it off, as I'm not going to risk what it may or may not then do, and then it refuses to start and I revert to disconnecting the battery and, so far, that allows it start and drive again without issue.

 

[Stuhart]

ML63 are disposable in Quatr,

Seems your indy is cluless, has he even read codes, did you see, he has no clue by the sounds of it - sorry but i would be fuming.

It's fair to say I'm less than delighted. I did witness the mechanic using his diagnostic computer at the first breakdown where he did show me an error code against the ISM and tried to reset it from there but without success. I don't claim to even remotely understand the electronic wizardry in these cars and I'm from a time where you fixed things with a hammer. Purely mechanical and I'm good but anything more intricate than a temperature sensor and I'm lost. However I do feel he's grasping at straws and just ticking things off one at a time (at my expense) without really identifying and addressing the root cause.

 

[mattkh]

Then approximately nothing. Electrics come to life but a turn of the key results in nothing at all.

Get a Auto-electrician to check and improve all the earth connections to the chassis and engine.
To your knowledge, does it have an after-market Alarm system.

 

[Stuhart]

Get yourself an MB specific diagnostic kit (£70-200 depending what you go for) and read the ECU looking for any fault codes. Disconnecting the battery suggests there is a fault code that's getting cleared. If there is a code resetting via diags is always preferable to disconnecting the battery and risking a surge destroying an ECU somewhere.

That does make sense however I'm not mad keen at throwing more money at a piece of kit that I'm probably not technically savvy enough to use and understand. Even if I pinpoint the problem I'll still probably be told that whatever unit is throwing the error can't be fixed and needs to be replaced. Previously in my life out here I've diagnosed the (mechanical) problems myself before going anywhere near a garage so at least they know I know what it's going to take to fix it so they are then less likely to diagnose issues that aren't there and make more money out of me. I would just like some confidence that I'm looking in the right areas hence the question regarding could the ECU be the culprit or am I being spun another yarn? I'm inclined to believe it could be the problem but I'm worried that if I go ahead and change it and it still doesn't work I'm not going to get my money back as the mechanic will just claim that it was still faulty and needed to be changed anyway and yet another problem exists. The never ending story.

 

[Stuhart]

Get a Auto-electrician to check and improve all the earth connections to the chassis and engine.
To your knowledge, does it have an after-market Alarm system.

Now that's something that I've never thought of before. As far as I know there's no aftermarket alarm. To be honest, out here nobody is worried about car security. In my 7 years here I've never heard or even read about anyone having their car stolen so I would assume it's standard. So, you're suggesting a dodgy Earth could potentially cause the ECU to lose it's memory, so to speak?

 

[Stuhart]

both issues u had fixed are normal Mercedes issues. But it sounds like the place u went to are guessing rather than diagnosing

the ecu might be faulty (as modern electronics don't last long) particularly if its been molested to tune it up, but I wouldn't expect its your issue

I feel exactly as you say that my mechanic is guessing. I don't know the history of the car but I'd be very surprised if the car's been tuned. Tuning is not really a thing out here.

 

[malcolm E53 AMG]

That does make sense however I'm not mad keen at throwing more money at a piece of kit that I'm probably not technically savvy enough to use and understand. Even if I pinpoint the problem I'll still probably be told that whatever unit is throwing the error can't be fixed and needs to be replaced. Previously in my life out here I've diagnosed the (mechanical) problems myself before going anywhere near a garage so at least they know I know what it's going to take to fix it so they are then less likely to diagnose issues that aren't there and make more money out of me. I would just like some confidence that I'm looking in the right areas hence the question regarding could the ECU be the culprit or am I being spun another yarn? I'm inclined to believe it could be the problem but I'm worried that if I go ahead and change it and it still doesn't work I'm not going to get my money back as the mechanic will just claim that it was still faulty and needed to be changed anyway and yet another problem exists. The never ending story.

You echo my sentiments entirely on ownership and maintenance but time moves on and with it technology so I’ve just bought myself an iCarsoft CR Pro so that I can diagnose MB and BMW faults as that’s what I own at the moment, tried it out on Sunday and I have to say I’m very impressed. If you do decide to buy use an official distributor so that there is no chance you will buy a clone item UK Parts Direct and Diagnostic World are official outlets - the former are very helpful so ask them on the phone whether the scan tool has the capability to do what you want It to.

 

[LostKiwi]

That does make sense however I'm not mad keen at throwing more money at a piece of kit that I'm probably not technically savvy enough to use and understand. Even if I pinpoint the problem I'll still probably be told that whatever unit is throwing the error can't be fixed and needs to be replaced. Previously in my life out here I've diagnosed the (mechanical) problems myself before going anywhere near a garage so at least they know I know what it's going to take to fix it so they are then less likely to diagnose issues that aren't there and make more money out of me. I would just like some confidence that I'm looking in the right areas hence the question regarding could the ECU be the culprit or am I being spun another yarn? I'm inclined to believe it could be the problem but I'm worried that if I go ahead and change it and it still doesn't work I'm not going to get my money back as the mechanic will just claim that it was still faulty and needed to be changed anyway and yet another problem exists. The never ending story.

Even if you don't understand what the diagnostic kit is telling you it will give you an error code you can Google or ask on here about. If there are no codes you can use that to argue with your mechanic (even though not every fault throws a code).
Diagnostic kit is not expensive. An Android based app/dongle like Autel AP200 is under £100 and iCarsoft dedicated readers are around £150.
The iCarsoft is generally better in my view but for ease of use the Autel would get the nod.

Make sure your vehicle is supported before buying anything.

 

[VicTealz444]

You echo my sentiments entirely on ownership and maintenance but time moves on and with it technology so I’ve just bought myself an iCarsoft CR Pro so that I can diagnose MB and BMW faults as that’s what I own at the moment, tried it out on Sunday and I have to say I’m very impressed. If you do decide to buy use an official distributor so that there is no chance you will buy a clone item UK Parts Direct and Diagnostic World are official outlets - the former are very helpful so ask them on the phone whether the scan tool has the capability to do what you want It to.

if you are referring to diagnostic-world.com, then I suggest you check out their customer feedback @ "Bavarian Dominator - Review Centre"

 

[malcolm E53 AMG]

if you are referring to diagnostic-world.com, then I suggest you check out their customer feedback @ "Bavarian Dominator - Review Centre"

Thanks for this and yes I used UK Parts Direct for that very reason who were extremely helpful

 

[VicTealz444]

Thanks for this and yes I used UK Parts Direct for that very reason who were extremely helpful

Good to know Malcolm. Will keep them in mind for future reference

 

[txfloydfan]

I have a 2009 ML63 AMG which I bought a few months ago and from almost day 1 I've been having problems. They started with the car failing to crank and appearing to be stuck in Park though the battery and all other electrics were working fine. Independent Merc garage mechanic (here in Qatar) diagnosed it as a faulty Intelligent Servo Module and replaced it at great expense. Almost immediately on its return it suffered the same issue again. Identical symptoms though the mechanic maintained it was a separate issue from the previous one and said this time it was an issue with the ignition barrel so the internals were also replaced at further expense. And guess what? Shortly after this it failed to start again! Identical symptoms once more. Now the mechanic is saying it's the ECU so I'll need a new of those too. To say I'm skeptical is putting it mildly. It may well be true but then I'm thinking was this the problem all along and the previous "fixes" were unnecessary? However, what I have discovered now is if I disconnect and reconnect the battery it would appear to reset itself and allows it to start so I'm doing this every morning to get it going and living with it like this for the time being while I decide if I really want to throw another sack of cash at a problem I'm not convinced is being properly diagnosed. Does anybody have any experience or an opinion on this?

I am having the exact same problems with my 09 ml. Did you ever find the problem?

 

[SL63 Mark]

I am having the exact same problems with my 09 ml. Did you ever find the problem?

The original poster was last seen in February 2022. This is a three year old thread. He has not been back since,

Hopefully he either got it fixed or sold the car.

Maybe start a new thread with your problem ?