Help My SL55 is sick

Help My SL55 is sick

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MercedesClassic

Original Poster:

891 posts

102 months

Sunday 28th January 2018
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Hi Folks,
Short version first - car won't start ESP - defective visit workshop. Indy thinks it's the EIS but needs the car in to run diagnostics.

More detailed version:
Ok so have had my SL55 since March and been great. Had an early oil & filter change few months ago and had both batteries changed as they are hard on batteries. That cured lots of the little silly warnings on the dash and meant I could leave it at least a few days and jump in and the electrical consumables being online.
Come December I noticed this was no longer the case even after 24 hours which was disappointing but a drive would rectify it.
Now to the main point of this posting. Driving home before Christmas Eve late at night I parked car to get a few things, got back in ESP - Defective Visit Workshop message on the dash and wouldn't start. Engine fan would come on and run, sounded faster and louder than I'd expect too.
Turned off, locked it, unlocked it tried repeatedly no go. The key would click to the second position but turning start did nothing except give the error above.
Now the key had been looking batteries so changed those but same. Called AA who put diagnostics on which gave a CAN comms error or something. He checked batteries, both perfect, both getting charge, fuses under bonnet box seemed fine.
My first thought was damp. Car got washed that day and guy was very thorough in around first arches and bottom of screen. However once fan eventually stopped I was able to start it up! Drove 30 miles home no issues.

Since then it's been parked at home and I am able to get it started occasionally to take it a drive to get charged up etc.
Last Saturday did the same and after a U turn (not sure if relevant) I was doing 50mph when the engine stopped and I coasted to halt. Called AA whilst waiting nearly got rear ended by a BMW overtaking the cars stopped behind me. Got car started, conked out on way home but made it.
AA diagnostics showed a string of errors none of which mentioned ESP which is what was on dash (sometimes ABS too), cleared faults. One fault remained 116 - coolant pump, charge-air cooler. Error Message: error detected.

I've it booked into Indy next week on brief description I gave he thought it was EIS related. Also the cold weather seemed to have contracted the roof/boot seals plus the rain has lead to some damp in cabin floor and also the PSE pump in boot has packed up. Can't open boot even with emergency key and can't lower roof as the divider is open!
I'm so annoyed especially since it died whilst driving which wasn't safe. Anyone got any advice? Could it be something simple?


OldGermanHeaps

4,094 posts

183 months

Sunday 28th January 2018
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Something is dragging the canbus down, stopping the cars various computer modules talking to each other, and as they are interdependant when they arent talking the car wont run. Because of the intermittent nature i'd agree water damage or wiring damage is a very good shout. Check all the usual water traps for signs of moisture, i'd start in the boot and work forward. Can you get access to a scope? You can split the bus at different locations and determine what direction the fault is coming from.
If i was a betting man i'd say there was a module taking swimming lessons in the boot, and unplugging it might allow the car to start, albeit with some dash lights on.
Maybe check marque specific forums for tips on how to get in the boot?
If you are really struggling to get in the boot are there any rubber bungs in the spare wheel well are you could pop from under the car to see if any water comes out?
While the car is sitting i would leave the battery disconnected and only reconnect it while you are actually working on the car, as if something is wet electrolysis will slowly be doing further damage.

Edited by OldGermanHeaps on Sunday 28th January 20:57

MercedesClassic

Original Poster:

891 posts

102 months

Sunday 28th January 2018
quotequote all
OldGermanHeaps said:
Something is dragging the canbus down, stopping the cars various computer modules talking to each other, and as they are interdependant when they arent talking the car wont run. Because of the intermittent nature i'd agree water damage or wiring damage is a very good shout. Check all the usual water traps for signs of moisture, i'd start in the boot and work forward. Can you get access to a scope? You can split the bus at different locations and determine what direction the fault is coming from.
If i was a betting man i'd say there was a module taking swimming lessons in the boot, and unplugging it might allow the car to start, albeit with some dash lights on.
Maybe check marque specific forums for tips on how to get in the boot?
If you are really struggling to get in the boot are there any rubber bungs in the spare wheel well are you could pop from under the car to see if any water comes out?
While the car is sitting i would leave the battery disconnected and only reconnect it while you are actually working on the car, as if something is wet electrolysis will slowly be doing further damage.

Edited by OldGermanHeaps on Sunday 28th January 20:57
Hey man thanks for the quick reply. I haven't been able to get into boot for 4 weeks as the PSE stopped working. I was able to open the bootlid that day whilst lowering the roof. I stopped it halfway to reach in and pull a wet towel off the pump. Relocated the divider before closing the roof. Unfortunately I haven't closed the partition correctly so I now can't open the roof either.
Real pain in ass. Got her started mid week to top up battery incidentally electrical consumers haven't been going offline which I thought was a good sign. However today it's worse the instrument lights are flickering wildly, going very dim at times and a bot of a clicking type noise. Like you say damp and electrics!
I can't disconnect the consumer battery as it's in the boot but this car has a new MB starter battery under bonnet.
I think you're right with the CAN Bus suggestion. Do you think it's going to be replacement parts or just get the damp sorted? I hope it's not big bills.

OldGermanHeaps

4,094 posts

183 months

Sunday 28th January 2018
quotequote all
Impossible to tell until you start stripping things. If the water damage hasnt been going on to long on a particular module isopropyl alcohol all over it then leaving it somewhere next to a dessicate sometimes works, but if its been live and wet for some time at a minimum you will need to resolder some rotten pcb tracks, replace connectors etc. Unfortunately it sounds like it been going on for a while and rather than investigate the root cause you have been hoping it would fix itself, that rarely works out unfortunately, older cars used to get a bit moody now and then but sometimes straigten themselves out, but electrical faults on complex cars tend not to. If you are paying someone else to do it big bills are very likely.
Picked up a few nice cars this way, as when the owner gets big repair estimates they end up selling the car for salvage money.

Edited by OldGermanHeaps on Sunday 28th January 22:30

Classy6

419 posts

182 months

Sunday 28th January 2018
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Sounds like water damage to me. It'll be a comms/CAN fault or faulty control unit. The reason the fan goes flat out is because the Engine CU is not able to communicate with anything so goes into a safe mode.

Used to find lots of water in footwells on SL's, from there usually heavy corrosion into the CAN blocks/terminals that sit in the under the door sill covers.

If it's a good indy, SL's have been around long enough now with these types of faults that it shouldn't be to heavy on the diagnostic labour.

MercedesClassic

Original Poster:

891 posts

102 months

Monday 29th January 2018
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Really pleased with the responses guys. Do you know a way I can get the car started to at least get her driven to the Indy? Otherwise I’m going to have to get it recovered in.
Had an SL500 R230 previously which was even more problematic it needed an ECU replaced by factory. Gave so much grief I swapped it for BMW 330i auto which never gave bother. None of the subsequent BMWs have.
Is it Mercedes in general or this era/model that’s particularly troublesome I wonder?
My 1994 SL320 has faults but it doesn’t leave me stranded.

DapperDanMan

2,622 posts

212 months

Monday 29th January 2018
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Because the key lock gets used infrequently it can get a little stuck. If the key doesn't unlock the boot then maybe try some PlusGas to free it up and turn the key and at the same time pull the boot release. It may take several operations of the key to free it up. NEVER FORCE THE KEY TO TURN.

I have also read of people breaking the rear brake light in the centre to get access.

Take a look at this YouTube https://www.youtube.com/watch?v=RfKJKHjxs-I

The seals on the brake light can degrade and indeed is one route water can get into the boot.

As for getting it started well as has been talked about you need to get the electrics dry (if it is water ingress) once the bus can communicate you may get it started.

You also mentioned a hot start issue which could be down to the main problem you have but can also be the crank position sensor which is cheap to buy and easy to fit (a little fiddly maybe)

MercedesClassic

Original Poster:

891 posts

102 months

Monday 29th January 2018
quotequote all
DapperDanMan said:
Because the key lock gets used infrequently it can get a little stuck. If the key doesn't unlock the boot then maybe try some PlusGas to free it up and turn the key and at the same time pull the boot release. It may take several operations of the key to free it up. NEVER FORCE THE KEY TO TURN.

I have also read of people breaking the rear brake light in the centre to get access.

Take a look at this YouTube https://www.youtube.com/watch?v=RfKJKHjxs-I

The seals on the brake light can degrade and indeed is one route water can get into the boot.

As for getting it started well as has been talked about you need to get the electrics dry (if it is water ingress) once the bus can communicate you may get it started.

You also mentioned a hot start issue which could be down to the main problem you have but can also be the crank position sensor which is cheap to buy and easy to fit (a little fiddly maybe)
Thanks man. Yeah the emergency key turns but the handle doesn't do much. You can hear the mechanism groaning as if it's trying to electrically/pneumatically activate but the PSE isn't getting pressure to it. I'm not technical in it so I hope that makes sense. The drain holes in the bottom of the boot have always been open too and the ingress hasn't been too bad.
Yeah I've seen the removal of the third brake light demos but knowing me I'd wreck something LOL.
Hot start no worse than cold start. Knowing my luck it will be mega bucks LOL

Classy6

419 posts

182 months

Monday 29th January 2018
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MercedesClassic said:
Really pleased with the responses guys. Do you know a way I can get the car started to at least get her driven to the Indy? Otherwise I’m going to have to get it recovered in.
Had an SL500 R230 previously which was even more problematic it needed an ECU replaced by factory. Gave so much grief I swapped it for BMW 330i auto which never gave bother. None of the subsequent BMWs have.
Is it Mercedes in general or this era/model that’s particularly troublesome I wonder?
My 1994 SL320 has faults but it doesn’t leave me stranded.
SL's particularly 230's suffered immensely with water ingress problems. The seals really suffer if left to neglect. It sounds like you have the common PSE pump underwater problem, too.

There will be nothing other than luck that you can do without knowing a bit more about the problem to get it going. From reading your posts, I would say it's not worth the risk either. Last place you want to be is stuck on a busy dual carriageway, no hard shoulder to find the car's cut out again. Just call your breakdown provider and get it recovered in, at best if they can wiggle some wiring and can get it going - ask that they FOLLOW you all the way to garage.

MercedesClassic

Original Poster:

891 posts

102 months

Monday 29th January 2018
quotequote all
Classy6 said:
SL's particularly 230's suffered immensely with water ingress problems. The seals really suffer if left to neglect. It sounds like you have the common PSE pump underwater problem, too.

There will be nothing other than luck that you can do without knowing a bit more about the problem to get it going. From reading your posts, I would say it's not worth the risk either. Last place you want to be is stuck on a busy dual carriageway, no hard shoulder to find the car's cut out again. Just call your breakdown provider and get it recovered in, at best if they can wiggle some wiring and can get it going - ask that they FOLLOW you all the way to garage.
My previous R230 SL500 did the same and it was only 5 years old at the time. Shocking lack of responsibility by MB at the time even though it had FMBSH.

I must say I'd not used the AA before until twice this past month and they have been brilliant. The first time was late night Sat before Christmas and was his last call out and despite living next to my incident he followed me half way home ie 15 miles. Probably helped that we kinda knew people in common who also stopped to help me. Wouldn't take a bottle of wine I offered him as thankyou.
Last Saturday the AA guy was really concerned about me as I nearly got rear ended by a BMW overtaking the queue behind me. He then followed me home to run diagnostics.
The AA app is brilliant just 2 taps and they're on their way. Hadn't to wait long and was kinda remote. Hopefully not need them again anytime soon though LOL.

rubystone

11,254 posts

264 months

Monday 29th January 2018
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....and this is why I bought an SLK55...I do hope you get it sorted though...

swisstoni

17,820 posts

284 months

Tuesday 30th January 2018
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Never go near an SL with a pressure washer especially round the side and bonnet vents.

I had a very aggravating time with my SL55 that would start one day and not the next due to over keen use of the above.

anonymous-user

59 months

Tuesday 30th January 2018
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I'd lay money on water ingress as above. I replaced all my boot seals on mine 3 years ago and have no issues with water, but can see why they leak.

Crap design, but a cracking car when they work.

MercedesClassic

Original Poster:

891 posts

102 months

Tuesday 30th January 2018
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I second all the above. I appreciate it's not easy sealing a folding roof but my BMW folding hard top was huge and yet never leaked power washing or not. Obviously Merc have the sealing perfected on other models just not the then flagship.
I've it leaks they don't care. Shameful.

MercedesClassic

Original Poster:

891 posts

102 months

Tuesday 30th January 2018
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I see there's a couple of guys on Ebay that repair PSE units. Does anyone experience of this? Are they repairable and is it a long term solution? Am I better buying a replacement?

bluesmoke2stroke

96 posts

113 months

Wednesday 31st January 2018
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with the boot..on mine ocasionally the lock seems to jam,no key will access it.i have to keep locking/unlocking while pushing the boot button and eventually it will clunk and be fine again for 6mnths.
while this is happening the car thinks the boot is open so the interior boot light is on thus draining the battery.
i took out the bulbs in the boot which cured the battery drain when the boot is stuck!
good luck

Classy6

419 posts

182 months

Thursday 1st February 2018
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MercedesClassic said:
I see there's a couple of guys on Ebay that repair PSE units. Does anyone experience of this? Are they repairable and is it a long term solution? Am I better buying a replacement?
If it comes with some guarantee and works after I can't see why not. Be sure to check that cost against what a new 2 yr guarantee on new unit would be though.

I would wait and see the extent of the damage is first (if water) or what the actual fault is before proceeding. Could just be corroded terminals on the PSE, or it's absolutely soaked inside. The roof pump is also in very close proximity and it maybe that if it's water at fault in the boot, your looking at other issues also in a preventative maintenance view. Could lead to new roof seals, clean up of terminals on other low sitting boot components etc also (not to put the fear of god into you!)

See what you're garage suggest, then you can start sourcing parts.