2005 SL500 won't crank over?

[Mercedeschris]

Hi all fairly new to this forum.
I have a 2005 SL500 that won't crank over. (I bought from an online auction site as on non runner) Done quite a bit of research which has lead me to th K57 relay in OSR boot area according to WIS. I stripped out all the trims to gain access to the said relay....and its missing? Does anyone know if this relay is only fitted to vehicles other than the UK market?
Every thing else worjs as it should. Interestly i found a pro forma invoice for parts and labour of almost £10,000 trying to fix this issue.........any advice really appreciated.

 

[Eddy77]

There’s a reason why this era of SL is cheap. Hugely complicated electrics. A lot of the modules are located in the boot and the boot seals are renowned for leaking. Water and electronics don’t mix. I don’t think you will get an answer here as it could be anything. You want to find a good independent Mercedes specialist and get them to run diagnostics using STAR tool. That will tell you where the fault lies. I don’t think trying random relays will fix it unless you are super lucky. It needs an expert to look at it with all the right equipment. Good news is that a lot of these cars have ended up uneconomical to repair so there’s a good supply of used parts on eBay and the like. Which will save a Bob or two. Get it into a STAR machine and take it from there.

 

[Deleted member 126969]

If it’s already had £10k spent trying to find the fault, I doubt it’s going to be a quick fix…..

 

[Accused]

I know its very obvious so forgive me for this but have you checked the crank position sensor, such a common cause on this engine

 

[Petrol Pete]

OP says it won't crank over, a faulty crank sensor will allow it to crank but not start. Buying a non running 16 year old SL from an online auction is a massive leap of faith from the OP.

Finding the £10K invoice would have been enough for me to call the scrap man.

OP , I wish you all the luck in the world .

 

[flowrider]

Hi all fairly new to this forum.
I have a 2005 SL500 that won't crank over. (I bought from an online auction site as on non runner) Done quite a bit of research which has lead me to th K57 relay in OSR boot area according to WIS. I stripped out all the trims to gain access to the said relay....and its missing? Does anyone know if this relay is only fitted to vehicles other than the UK market?
Every thing else worjs as it should. Interestly i found a pro forma invoice for parts and labour of almost £10,000 trying to fix this issue.........any advice really appreciated.

For £10k they could have just replaced the engine!

 

[Smiley]

A proforma invoice is an estimate for work to be carried out - not an invoice for work completed. It may have been prepared to justify writing the car off. It does not necessarily mean that whoever prepared the proforma was/is correct of course. If the car was cheap enough then why not have a go?

 

[Petrol Pete]

Good point Smiley , OP , How much did you pay for this car ?

 

[DrNick]

Must be a fairly limited set of reasons for why it wont even crank!
Surely the first thing would be to check it can even rotate to cross off a seized engine.
Does the immobiliser of these allow it to crank?
Sounds to me that the previous owners have a good idea as to what the problem is and have unloaded it. Maybe the relay has been removed to cause the non-crank issue to disguise the real issue!
Maybe I'm too cynical.

 

[Mercedeschris]

There’s a reason why this era of SL is cheap. Hugely complicated electrics. A lot of the modules are located in the boot and the boot seals are renowned for leaking. Water and electronics don’t mix. I don’t think you will get an answer here as it could be anything. You want to find a good independent Mercedes specialist and get them to run diagnostics using STAR tool. That will tell you where the fault lies. I don’t think trying random relays will fix it unless you are super lucky. It needs an expert to look at it with all the right equipment. Good news is that a lot of these cars have ended up uneconomical to repair so there’s a good supply of used parts on eBay and the like. Which will save a Bob or two. Get it into a STAR machine and take it from there.

Thanks for your reply...I do know someone with a STAR machine....Ill let you know..

 

[Mercedeschris]

Good point Smiley , OP , How much did you pay for this car ?

£2000

 

[Mercedeschris]

A proforma invoice is an estimate for work to be carried out - not an invoice for work completed. It may have been prepared to justify writing the car off. It does not necessarily mean that whoever prepared the proforma was/is correct of course. If the car was cheap enough then why not have a

A proforma invoice is an estimate for work to be carried out - not an invoice for work completed. It may have been prepared to justify writing the car off. It does not necessarily mean that whoever prepared the proforma was/is correct of course. If the car was cheap enough then why not have a go?

The invoice/proforma was not paid...the repairer wrote the bill off i assume. I thought if I cant fix it I would sell it off for parts and still make a few quid?

 

[Mercedeschris]

Must be a fairly limited set of reasons for why it wont even crank!
Surely the first thing would be to check it can even rotate to cross off a seized engine.
Does the immobiliser of these allow it to crank?
Sounds to me that the previous owners have a good idea as to what the problem is and have unloaded it. Maybe the relay has been removed to cause the non-crank issue to disguise the real issue!
Maybe I'm too cynical.

I can crank the engine over by putting a feed to the starter motor. But wont fire up. All sorts of CAN BUS faults stored, so working through those to see what I can find. I can get a guy with STAR to plug it in but he's too busy to get to me for weeks.

 

[Mercedeschris]

I have removed the boot trim panels to check components in there and found that the K57 relay is missing. Anybody know whether this relay is "market specific" ie USA only etc??
It controls connections between the 2 batteries from what I understand. Mounted next to N82 unit on right side wheel arch in boot.
Many thanks for any info

 

[Petrol Pete]

Reads like someone left the roof open during a rain storm or storms plural.

 

[kcsun]

It may pay you to hire someone else local with a Star rather than wait for your friend, save hours of guessing

kc

 

[Mercedeschris]

Forgot to say the cars bone dry in boot and foot wells. Ive attached some photos of the relay thats missing on my car....

 

[Mercedeschris]

SORTED After "pin checking" almost every wire on the car. I was 99.9% sure I had a faulty ESP module. I then notice that the CAN high wires (green/white & green) had been by passed and connected the the engine ECU?? I reconnected the wires correctly, I then noticed that the CAN high waveform was now incorrrect. If I disconnected the ESP module the signal was good. A friend of mine has a similar car, so I swopped the modules over and my car fired up straight away......his car woudn't start. So after about 20 hours of research and reading WIS wiring diagrams, problem solved. I may let the MB specialist know LOL they spent £10,000 and 13 months trying to fix it..
Cheers
Chris

 

[DrNick]

Good find! Looks like a cheap car. Any other issues yet?

 

[Mercedeschris]

Battery light ia on dash constantly? I think comsumer battery is dead. Other than that so far so good.