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Marty, European Car Expert
Category: UK Car
Satisfied Customers: 54039
Experience:  ASE & Bosch Certified Master Tech. Over 30 years experience.
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sl500: I have a 2005 SL500. The ABC white light is on permanently.

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I have a 2005 SL500. The ABC white light is on permanently. The car was not used for a period more than 1 year. Car works fine. Hydraulics work ok. Car is not leaning. Height stays normal. ABC Sport and normal modes work ok. No leaks.

I had the car diagnosed and it pointed to an error B4/5 which was the pressure sensor.

Would like to know if it can be serviced DIY (if its a contact problem) or maybe change the switch by simply unscrewing. I have read the car must be off and preferrably cool before touching it. What is the advice? Access to parts where I am is difficult and cant seem to read the part number off the vehicle but I have a picture of the pressure sensor. Will simply unscrewing and screwing back take care of any possible contact issues (if thats a possibility)
Hi, I'm a Moderator for this topic. I've been working hard to find a professional to assist you right away, but sometimes finding the right professional can take a little longer than expected.

I wonder whether you're ok with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, please let me know and I will cancel this question for you. Thank you!
Customer: replied 4 years ago.

I am a little surprised this answer is taking so long. I thought u had experienced Mercedes personnel on ur list?


I would wait a little longer.

Thank you for your continued patience. We can not predict or guarantee response time, just because the volume of questions, number of professionals online, complexity of questions, and other factors vary. We will continue the search for a professional for you.
Hi, and welcome. My name isXXXXX apologize for the wait I was away this weekend.

Can you please post your 17 digit vin number for me.?
Customer: replied 4 years ago.
My vin is WDB2304751F093149
Thank you for the vin number. The pressure sensor on your Mercedes is not serviced separately. If the sensor is faulty you will need to replace the valve unit part number 220 320 08 58. The part retails for $1000. There is a seal kit available for the sensor if it is leaking fluid. The part number is XXXXX 320 11 58 and it retails for $70. I'd inspect the sensor for leakage and inspect the wiring to the sensor to be sure it hasn't been chewed by a rodent while the car sat for a year. It is not unusual to find rodent damage to the wiring when a car sits for so long. You should have 5 volt supply voltage to the sensor on the black/red wire and ground on the black/brown wire. If everything checks good you will most likely need to replace the valve unit to repair the problem. If you need to reseal the sensor you can just unscrew it and replace the o-ring. You can also try removing and blowing out the port in the sensor with compressed air and see if that gets it working again. The valve unit is not difficult to replace but you may need to have the car connected to the Mercedes Star Diagnosis tester to erase the fault codes when completed. I've attached the instructions below for the replacement of the valve unit. Please let me know if you have any questions.

Replace Valve Unit
Remove Pulsation Damper
Remove Fender Liner
Customer: replied 4 years ago.

my partGood day


Thanks for the reply. I still have just a clarification. In the diagram, what is indicated is that Part B4/5 is faulty. From your reply, it seems Part B4/5 is sold along with Part 52.


But what I would like to clarify is this: I assume that Part B4/5 is the one u can remove to reseal if there is a leak. So then, why cant I just go to a used car lot and simply get another Part B4/5 and replace instead of replacing Part 52?


I am attaching a picture of my system. I have confirmed there are no leaks. I will inspect the wiring in the mean time






Hi Dami, yes that is correct. The seal kit is for the B4/5 sensor. You can absolutely go to a salvage yard and purchase the sensor if they will sell it to you.
Marty, European Car Expert
Category: UK Car
Satisfied Customers: 54039
Experience: ASE & Bosch Certified Master Tech. Over 30 years experience.
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Customer: replied 4 years ago.



Finally, can I get the part number for the B4/5 sensor just in case I need to search for it?





Hi Dami, Mercedes no longer lists the B4/5 in the parts catalog.I believe the old number was 012 542 92 17 but I doubt you will have any luck finding one.