abstar

Hi guys new to this forum and read many interesting and informative threads so was looking for some help to an abc problem on a 2003 s600 the light is obviously on and the pressure starts at 180 bar and will gradually decrease to 0 bar now the car was garaged for about 2 years and not driven and had no problems beforehand the error code is c1526-016 so the question is would it be the pressure sensor or the accumulator attached to it or more sinister the pump but if it were the pump shouldn't I have no pressure at all rather than diminishing pressure hopefully someone has had the same issue and can help
thanks in advance

MJ50

moved to W220 forum...

ibeforreal

Welcome to the forum Abstar.

Since it has been sitting for 2 years with no driving there are lots of possibilities. Your best bet is to find someone with a STAR diagnostics system to check everything out before spending a lot of money on parts that may not be necessary. One possibility you may want to consider is having the ABC system flushed. If you have no experience doing such a thing it would be best to find a good INDY who could help you out. The ABC system is very delicate and the least amount of contamination could cause major problems.

tusabes

Could be the valve blocks sticking open

theres a guy on eBay who rebuilds them for $125

i would first have the valve blocks rebuilt , if that does not help then try a rebuilt acdelco abc pump from rockauto for $250

abstar

thanks tusabes
but it's the pump losing pressure that I'm stumped with because the hydraulic pump should either work or not ..not produce pressure then slowly lose it with all that I've read I believe the pressure sensor controls the pump on when to produce pressure or not so I'm leaning to that in regards to the valve blocks I thought they control the pressure to the struts once the system has pressure I have a guy coming over with star to diagnose so I'll see what that shows up as the previous person said
thanks again

alexanderfoti

Suction valve bolted to the pump is stuck.

Front and rear valve blocks open/close very quickly to maintain level, if they where stuck, then one corner/end of the car would be either on the floor or up in the air fully.

Welwynnick

Can you explain everything in as much detail as you can please?

How do you know 180 bar? Do you have MB STAR?

What are the circumstances for the pressure drop? What si the car doing?

Is the suspension sitting at normal height?

Does it respond to the height control?

Nick

abstar

hi alexanderfoti
would the suction valve need to remain closed to maintain pressure? If there were a small leak in the seals of the suction valve that would explain the inability to maintain pressure yes ?
Thanks for your input

alexanderfoti

Suction valve is modulated by the ABC ecu to maintain pressure under load. If its stuck closed you will only get a smalll amount of pressure under demand (actuation valves) pull the pressure below the limit.

However, answer Welwynnicks questions as its important to know this information to provide an accurate diagnosis.

abstar

hi welwnnick
I have a diagnostic scanner that can read the abc system but is not star as in my original post the fault cobe is c1526-016 malfunction in pressure supply and it shows me 170-180 bar on start then gradually decreases 1 bar at a time like a count down clock it will respond to height control as if I leave the car for a few days it does sag but I know this is the valve blocks and have seal kit at the ready to install but want to sort out the maintaining of pressure
thanks again for any assistance