SL500, 2003: Central locking not working from key, door buttons or lock switch on dash board. Roof not opening, cigarette lighter not working. Consumer battery has been replaced, fully charged, windows and ESP reset. Door locks and trunk can only be locked and unlocked with an emergency key.
Country: New ZealandMake: Mercedes-BenzModel: SL500Year: 2003Engine: V8 4966 cc
Please see the original question which has set out the details.
Hello,There is a fusebox under right rear load compartment, which has a fuse for central locking. Please check all fuses there first of all.
The car is currently at an auto electrician. They have opened the box under the rear pacel box and exposed the fuses. I assume those have already been checked. They have also dismantled the the boot lock mechanism, a lot of the wiring in the trunk is exposed. After two days they still have not identified the fault. I did not say what had already been tried because I do not know exactly. All I have done is, replace the battery with a new one, fully charged it, reset the windows and the ESP. The car starts with the plastic key and the doors can be locked with the emergency key. I have replaced all the batteries in the keys and the "Keyless Go". I understand that I have to have the "Keyless Go" reprogrammed by an MB dealer. Unfortunately there are very few, if any, of these cars in Nelson, where I am located. What I am hoping to do is perhaps get some information that will help the electricians to pin down the problem.
I forgot to say, when the key buttons are pressed, the alarm sets and the lights flash. Pressing unlock turns of the alarm and the lights flash again.
Ok, it seems that PSE module (pneumatic system for actuating central locks, controlling alarm and door statuses) has failed. It is located at the left side of the trunk, below hydraulic pump for convertible roof
please have the electricians disconnect it- this might reset it.
Also let them open PSE module to see if any water got on it's internal electrical plates
A very common problem is that electric motor for vacuum/pressure pump fails- so it is good to check it's resistance and how it runs when car is locked/unlocked
It is also inside the PSE module. If it fails- door position signals will not be clear for convertible roof and it will not work
That is interesting. If I try to open the roof there is a pulsing noise from the area of the pump. It continues for a while then stops. It also stops if I restart the car but if I touch the roof switch again the pulsing starts. Also I think I noticed it starts if I touch the door handle but I am not certain.
There are two pump modules there- one is PSE (pneumatic) and one is hydraulic for the roof. Hydraulic is right on top of PSE. It is quite hard to detect which one starts making noise.
Thanks, I can't do anything until Monday. I will pass on your information. I will click the accept button. How can I contact you again if I need to?
But if hydraulic one starts running, but roof does not open- i suspect a problem with roof position switches. It is best to have this issue checked out with Star Diagnosis computer- some independent Mercedes shops have it besides the dealers. This tool is needed to communicate with PSE, Convertible top and all the rest of controllers
Save a link to this internet page, and even after accepting, you will be able to post a reply. I will get back to you as soon as possible
We can communicate on this matter for as long as necessary.
Thank you very much Stan.
Sorry, you do not have my name.
Technical support engineer
Hello Stan,The auto electrician sent the PSE pump to an electronics repair company. They could not find anything wrong. It was then tested using the STAR diagnostics at the Mercedes dealer. That showed that the system was not working but did not, specifically, identify the pump as the problem. What it did show was that the system shows the driver's door as being always open. The electrician proposed that that I replace the pump. The price in NZ is absurd $3,400. I can buy the pump in the US for $690 and in the UK for £595.Next week I am going to Europe until November and I will be in the USA for a month in July. Plan to buy the parts I need in one place or the other. Can you tell me if the US version is only for LHD or is the pump common to LHD & RHD versions? I also propose to replace the timing belt as a precaution since I do not know its age. The car has covered 41,000 miles. I would appreciate your comments.David.
Hi David,Your SL has a timing chain, which does not require servicing. Ideally, it should last a lifetime of engine. No need to replace it unless there is noise coming from chain drive, or engine runs uneven/misfires.Please let me know the VIN of your car, i will tell you the part numbers suitable for your car. It might be quite difficult to find a PSE, because it is specific for SL. It is not specific to LHD or RHD though- it must be coded to your car with Star. I have one at hand right now with blown air pump/motor but working electronics. Actually i am quite skeptical about PSE being bad. It seems that a door position microswitch is bad, or door control module is sending wrong info over CAN lines.It would be good to evaluate the diagnosis steps of Mercedes dealer, which has led them to conclusion that PSE is the causeRegards, Stan
Thanks for the reply.I am sure that the auto electrician has tested the micro switch. He mentioned the CAN lines. I have to be very careful passing on information to him as he is very "touchy". Before I gave him the info about the pump he had already removed it and sent it for test. He did not welcome the advice. On the other hand he did not tell me that he had done that. I use, faithfully, a local repair garage who have for years been very good looking after our other cars. They referred the SL to the auto electrician. The MB dealer brings to mind "wounded bulls". I had not appreciated the complexity of this car and my regular garage believed that they had the correct software. It may be more efficient to use the MB dealer in this instance but I quail at the cost. Everything they have quoted so far has been 2-3 times the price for the same items in the UK or USA. e.g. I had to replace the consummer battery as soon as the car arrived, from the UK - it was stone dead - the dealer price was $840, US price US$125 (NZ$165) and the Americans thought that was expensive.The belt: there is a long flexible belt on the front of the engine. I assumed that this was a timing belt. I had an MB 230 that lost a similar belt between services and put a valve through a piston, that is why I am concerned.David.
Sorry I omitted the VIN.
Hi David,Pump's number suitable for your SL is A2308000448.One possible way to confirm if PSE is bad is to install it on a properly working SL. The same pump was used from start of production to 2006.I have not heard of any engines failing because of V-belt failure. It only turns alternator AC, power steering and water pumps. Check with your trusted electrician, maybe there are some independent Mercedes shop with Star Diagnosis in your area. That would give your electrician possibility to see the whole picture. I understand how hard to diagnose such system without seeing what the control units think and see. And there are few dozens of them in SL.Best prices for parts are in Germany for new original parts. Regards,Stan
Thank you Stan,I am leaving this week and the car will be in our garage until November/December. I have bought 2 CTEK 4003 chargers, one for each battery. I cannot find, on the Inet, a specification for the starting battery. I need that to set the correct mode on the charger. The Consummer Battery I understand is AGM so I am using the "Snowflake" setting as recommended by CTEK. Is the Starter battery also AGM? I have seen on e reference saying it is a GEL type. The battery ref numbers are Varta, A 230 541 00 01, 12v 35ah 520 A (EN). It is Mercedes branded.Thanks David.
Hi David, Leave it on the snowflake (minimum charging) as well. I am on the move right now as well, and will be able to re-check the battery type and rating next week.Regards, Stan