W221 S500L ECU gone

[imranrz]

I m driving W221 S 500L milage is only 32000 & suddenly facing engine control unit issues, starting issues when engine is hot it took me abt 2 weeks to diagnose this issue by the authorised dealership we thought it might me issue of some relay or rear Sam etc but finally it was ECU

 

[imranrz]

I m driving W221 S 500L milage is only 32000 & suddenly facing engine control unit issues, starting issues when engine is hot it took me abt 2 weeks to diagnose this issue by the authorised dealership we thought it might me issue of some relay or rear Sam etc but finally it was ECU

I m shocked about the reliability of Mercedes Benz my car is as good as brand new condition very low milage 6 months ago air injunction pump stopped working I replaced the new one now ECU gone... Please advise shall I get rid of S class

 

[imranrz]

I m driving W221 S 500L milage is only 32000 & suddenly facing engine control unit issues, starting issues when engine is hot , engine crank but engine doent start it took me abt 2 weeks to diagnose this issue by the authorised dealership we thought it might be issue of some relay or rear Sam etc but finally it was ECU, I was really shocked the price given by the Mercedes dealership was abt £2500/- for new ECU + labour, 6 months ago air injunction pump stopped working I replaced new one & now ECU what a reliability of S class...
Please advise shall I get rid of S class & buy a Honda or Toyota which are the best in reliability, please advise.

 

[Borys]

Get a second hand opinion first from merc specialist then decide

 

[imranrz]

Get a second hand opinion first from merc specialist then decide

Thanks bro but they don't have second hand option for ECU only have to order new one frm Germany, you can't get ECU, car key & lock second hand.

 

[Diesel Benz]

Thanks bro but they don't have second hand option for ECU only have to order new one frm Germany, you can't get ECU, car key & lock second hand.

Maybe a second opinion then instead of a second hand opinion (or second hand option).

If your symptoms are problems for the engine to fire up when hot, it could well be a CPS or camshaft position sensor (there was even a recall for these at some point for the W221).

 

[imranrz]

Maybe a second opinion then instead of a second hand opinion (or second hand option).

If your symptoms are problems for the engine to fire up when hot, it could well be a CPS or camshaft position sensor (there was even a recall for these at some point for the W221).

My dear issue is car starting problem when engine goes hot on some certain temperature starting in morning is perfect no issue at all but after driving few hours I park the car & about after an hour interval if I start the car ECU don't give current/power to fuel pump but when engine temperature goes down to normal it start perfectly . PLEASE ADVISE.....

 

[Borys]

Sorry guys for my English
Where is the ECU located?Spoken with my merc guy,he never heard of ecu failing on w221.He said if ecu is located on the engine because of the heat,when warm it may brake down then-that is why you have cold ,hot start issue.
Anyways without looking on paper work you have from dealer hard to say and looking on the car
That is why I suggested second opinion from other place
You don't want to change ecu and car will still not run,dealership like to put customers in situations like that lol

 

[imranrz]

Sorry guys for my English
Where is the ECU located?Spoken with my merc guy,he never heard of ecu failing on w221.He said if ecu is located on the engine because of the heat,when warm it may brake down then-that is why you have cold ,hot start issue.
Anyways without looking on paper work you have from dealer hard to say and looking on the car
That is why I suggested second opinion from other place
You don't want to change ecu and car will still not run,dealership like to put customers in situations like that lol

I am Totally confused bro I don't knw what else shall i do because the authorised dealer diagnosed that the issue in this case is only Engine control Unit, you are right it's very rear ECU failing but that's what they told me... Please advise I can go for any sort of experiment before ordering the new ECU.

 

[Borys]

Where about are you?

 

[Howard]

Does this not sound like a crank or cam position sensor ?

Classic symptoms.

 

[Borys]

My mechanic mentioned that as well, but was blaming more the fuel pump?

 

[andy27168]

Hi,
This sounds very much like the Crank position sensor (CPS), and as it is a very common issue, and against the price of a new ECU it is cheap to do I would be insisting on doing this first. To be honest if the symptons are as you described I amazed a main dealer has,nt replaced it already.

 

[imranrz]

Hi,
This sounds very much like the Crank position sensor (CPS), and as it is a very common issue, and against the price of a new ECU it is cheap to do I would be insisting on doing this first. To be honest if the symptons are as you described I amazed a main dealer has,nt replaced it already.

Thanks's for the advise let me ask them to check or replace CPS first & than get back to U guy, thanks a million for the help

 

[Diesel Benz]

If your symptoms are problems for the engine to fire up when hot, it could well be a CPS or camshaft position sensor (there was even a recall for these at some point for the W221).

Does this not sound like a crank or cam position sensor ?

Classic symptoms.

Hi,
This sounds very much like the Crank position sensor (CPS), and as it is a very common issue, and against the price of a new ECU it is cheap to do I would be insisting on doing this first. To be honest if the symptons are as you described I amazed a main dealer has,nt replaced it already.

There may not be a fault code from a misbehaving CPS or camshaft sensor but it is easy to check with Star if the ECU obtains timing info when the engine is started.

How did the workshop figure out it could be the fuel pump? Was it just speculation?

 

[imranrz]

There may not be a fault code from a misbehaving CPS or camshaft sensor but it is easy to check with Star if the ECU obtains timing info when the engine is started.

How did the workshop figure out it could be the fuel pump? Was it just speculation?

Sir let me explain u little bit more I went to authorised dealer ship to diagnose that issue they kept the car in workshop for 2 days it start perfectly normal they went for test drives also checking the starting for car in different intervals but third day that issue came again we drove the almost all day & in evening I stopped somewhere switched off the ignition after about 45 minute I came back & pushed the start button engine cranked but doesn't start luckily the mechanic was me I had to drop him somewhere he had the tools with him to check current/ power etc he fixed that meter in rear Sam & I was try trying to start the engine after trying several times he said the fuel pump is not getting any power when we were try to start engine, he said he is pretty much sure it must be ECU (engine control unit) fault all the relays & other related things are OK...
Please Advise......

 

[Diesel Benz]

Sir let me explain u little bit more I went to authorised dealer ship to diagnose that issue they kept the car in workshop for 2 days it start perfectly normal they went for test drives also checking the starting for car in different intervals but third day that issue came again we drove the almost all day & in evening I stopped somewhere switched off the ignition after about 45 minute I came back & pushed the start button engine cranked but doesn't start luckily the mechanic was me I had to drop him somewhere he had the tools with him to check current/ power etc he fixed that meter in rear Sam & I was try trying to start the engine after trying several times he said the fuel pump is not getting any power when we were try to start engine, he said he is pretty much sure it must be ECU (engine control unit) fault all the relays & other related things are OK...
Please Advise......

I should leave this for the engine experts, we have real experts on-board. The workshop could have monitored the real fuel pressure but since it is much more difficult than reading sensor readings from SDS, I would have started by verifying the presence of timing signals (camshaft and crankshaft).

I wonder if the workshop expert took into account that there is a generic design rule for the fuel pump: the pump is initially activated but if no engine speed signal is detected, the pump is shut off. You can ask the expert to have a look at this document: gf07.61-p-3018v.

Guess where the engine speed signal comes from.

 

[imranrz]

I should leave this for the engine experts, we have real experts on-board. The workshop could have monitored the real fuel pressure but since it is much more difficult than reading sensor readings from SDS, I would have started by verifying the presence of timing signals (camshaft and crankshaft).

I wonder if the workshop expert took into account that there is a generic design rule for the fuel pump: the pump is initially activated but if no engine speed signal is detected, the pump is shut off. You can ask the expert to have a look at this document: gf07.61-p-3018v.

Guess where the engine speed signal comes from.

Sure thanks... Let me forward all these expert opinion to the local Mercedes workshop tomorrow morning & get back with the final result. Thanks a lot one again to all for the concern & expert opinion

 

[imranrz]

Sure thanks... Let me forward all these expert opinion to the local Mercedes workshop tomorrow morning & get back with the final result. Thanks a lot one again to all for the concern & expert opinion

Dear Mr Diesel Benz,

I spoke to the authorised Mercedes workshop which is fully equipped as per Merc standard they have a question : while checking the fuel pressure & timing signals etc as briefly mentioned by you in case of any fault appears it will show on the computer screen or not & if not than how to deal with this. ???

 

[imranrz]

Dear Mr Diesel Benz,

I spoke to the authorised Mercedes workshop which is fully equipped as per Merc standard they have a question : while checking the fuel pressure & timing signals etc as briefly mentioned by you in case of any fault appears it will show on the computer screen or not & if not than how to deal with this. ???

Dear Mr D Benz,
This is the mail I just received from Worksop to forward to experts :

Dear Sir,

The Engine Control Unit stores Fault if the CPS(Crankshaft Sensor)does not
give or give implausible value. Secondly, If the fuel pressure starts
trouble, it is permanent not an occasional fault.

Regards,


-----Original Message-----
From: Imran [mailto:[email protected]]
Sent: Friday, March 15, 2013 11:35 AM
To: [email protected]