96 E300D P1622 Error
 

My car has this error and it will come and go intermittently. According to the code reader at the ind shop in town it means "error in shut off valve circuit" or something like that. Car starts and stops and runs great. Shut off valve and o-ring were leaking like sieves and were recently replaced. The error code predated the shut off valve replacement and has come back. Any thoughts? My local mechanic sort of shook his head and said maybe the wiring harness and maybe the engine data computer.

I do not have first hand expirience with that code.

If it were mine before I did either of those expensive repairs I would consider replacing the K40 relay. It provides electrical power to the shutoff valve. When it faults, it cuts power to the shut off valve causing the valve to shut while driving as if key were turned off.

You dont seem to have that problem, but.....the K40 is VERY cheap compared to the other two.

TMA has a good point as the K40 relay is the power supply...

The reason that that code is registered is: the IFI computer checks for current draw from that solenoid..should be 1-2A..if the draw is too high or low that code is registered.. SINCE the new lower sulfur fuel appeared in June we have been selling about 25-30 a month of those actuators....000-078-44-49

M.B. Doc - what actuator are you referring to selling 25-30 per month?

Thanks for your help as I try and get this car in shape.

That part number is the shut off valve whcih you have already replaced.

Or did you only replace the o-ring? If so, the fault means the valve may be bad also.

If the valve is new the fault may be caused by the K40 relay powering the valve.

Last week we replaced the shut off valve with a new one from MB and the o-ring. I will check the k40 relay.

You can look at the circut board with a magnifying glass and attempt o locate the cracks that cause the K40 to fail. Pretty tedious to try to solder them IMHO, but some have done so with good result.

Does it affect the 210 turbodiesels too? Like the 99 E300?

Very tedious. If I had gotten it on the first try, it would have been worth my time. Taking it apart a second time and doing a better job took a second hour, and I should have either done it better the first time or gotten a new part.

If you do try to solder it, here are some tips that I learned. First, use a small die grinder (or Dremel tool) and grind the tips of all of the high-current leads until you see the base metal: the bars and the high-current relay contacts. Solder them with a powerful iron. This will help the solder bond to the connector.

Use a big enough heat source to do the soldering. I used a butane-powered iron the second time, supposedly 180W equivalent, but it worked much better than a 140W electric soldering gun. Don't even bother trying to solder these with a standard soldering iron. It won't get the joint hot enough to get a good bond.

After soldering these, let the board fully cool and solder the coil connections for the relays. You will almost surely have moved the relay position on the board just enough to make these fail; I did. You can use a standard soldering iron for these, and I recommend it. You don't want to damage the relay coil connection.

If mine fails again within the next ten years, you can probably guess what I'll do.

IS the dealer the only place to get the exact error code? I am getting the PO200 after replacing the Glowplugs but it is a generic code and I was told only MB can provide the exact code. Is this correct?