Vito w639 Engine light and limp mode help!

[Meggerman1969]

Mercedes Vito w639 111cdi 2005.
Hi all. I'm having a hard time getting this sorted! When I accelerate and the auto box changes up a gear, as I keep accelerating the engine goes into limp mode. If I accelerate but back off as it changes up a gear, it doesn't go to limp mode!! I've had it into Merc and plugged in. They replaced the boost sensor, but no help!! No codes came up at Merc!!

 

[whitenemesis]

Try a different dealer or better still an independent with STAR experience
There's always codes, may not be current or pertinent but there's always codes.
Should be cleared and the vehicle run to see what comes back..

 

[Meggerman1969]

I also forgot to mention, if I turn it off and on again even while moving it will reset and run fine until the next hard acceleration!

 

[mushr00m]

please add a picture of what they changed. Just make this clear in my head. It does sound very much like the solenoid actuator. known as a turbo transducer. like this picture.

I trust this is what you are referring too. If not, this is what i would consider the fault. No this does not always produce a code. However, if you disconnect this item and then try to drive, yes it will. however, if this present and not fully working then no this wont produce a code. This was my issue for many many months. I decided to try and fix this myself and found this to be the fault. I tried a known working one and that was also DOA. So a brand new one from china, errr yep you heard me right. Sorted it out just fine and now have turbo all over the place. My problem would occur at 60,mph or higher then 5th gear and limp mode started. The power dropped off after 50mph. Change down and still no power. Turn off and turn on during drive would clear the issue only to repeat the same failings.

 

[tjamesbo]

Check your hose from turbo to intercooler they split with age mine 2007 was split
Boyd

 

[Meggerman1969]

please add a picture of what they changed. Just make this clear in my head. It does sound very much like the solenoid actuator. known as a turbo transducer. like this picture. View attachment 108176

I trust this is what you are referring too. If not, this is what i would consider the fault. No this does not always produce a code. However, if you disconnect this item and then try to drive, yes it will. however, if this present and not fully working then no this wont produce a code. This was my issue for many many months. I decided to try and fix this myself and found this to be the fault. I tried a known working one and that was also DOA. So a brand new one from china, errr yep you heard me right. Sorted it out just fine and now have turbo all over the place. My problem would occur at 60,mph or higher then 5th gear and limp mode started. The power dropped off after 50mph. Change down and still no power. Turn off and turn on during drive would clear the issue only to repeat the same failings.

I haven't had any turbo or power loss. Mine just goes to limp mode, then I switch off and on quickly and it's back to normal! That's why I was miffed when Merc swapped the boost control sensor. I'm thinking it's the EGR valve, as when it accelerates that's when the exhaust gases build and the limp mode kicks in. If I back off for a second, the limp mode doesn't kick in! I'll see if I can find a pick of the replacement part! Thanks for your time to reply.

 

[m80]

This may be different on earlier 639's.
When you cycle the ignition the turbo actuator may do a full action as a self test.
With some one turning the ignition to 2nd position you might look at the actuator to see if it travels full distance.
Actuator can fail,
turbo veins can seize with rust / carbon.

If you remove the actuator arm from the turbo be careful not to lose the circlip.

 

[m80]

You can maybe free up the EGR with wire wool, plus gas and an overnight soak. Manipulate it to free it and soak again.

Very awkward to remove if it's not been out for a while, 2 bolts out and then manipulate clockwise / anti clockwise for an hour or three.

 

[Jigglyjohnson]

Sounds like a boost pressure issue as u hard accelerate the pressure builds up to much and vehicle enters limp mode. Test all vac actuators as per above and also any vac lines for defects best to use a vac gauge to be 100% as the naked eye can miss a pin hole

 

[Meggerman1969]

Thanks for the replies. I'll try that when the weather clears up and let you know!!

 

[mushr00m]

simple answer to look for.. Can you drive above 65mph. If you cannot achieve up and beyond 65mph, then i strongly check the transducer. Even to get upto 50mph should be simple but to get beyond 65mph it will struggle. If this is indeed the case that you cannot get above 65mph without hitting limp mode then yes, its a good chance your transducer is at fault. However, the EGR is another simple check. Pull off the vaccume tube to the EGR valve unit. This prevent the vaccum from opening the recircing the gases thus suffocating the air feed to the engine. Pulling this pipe off will tell you if the EGR is the issue. Personally speaking. Floor it to 65mph and beyond if it fails then think about the Trans as your issue.

 

[mushr00m]

with the above being said. try 2 methods. 1st floor it and see if you can get 65mph. 2nd try, gradually get to 65mph without flooring it. See if you can get above 65mph with no problems.

 

[Meggerman1969]

Hi, thanks for the information! I can get to 70 easily enough, just have to switch off/on ignition if light comes on! So if I pull the vacuum pipe off the EGR so it can't open, that should cause the engine to suffocate?

 

[mushr00m]

This a view from a TDS family BMW. Notice there are 4 passages. in and out maybe wrong but theory is correct. Remove Vac and bypass = side additional is the recirc gasas. Block of the side additional and NO recirc gasas can enter your air circulation system. Which is the problem for the EGR system. Pulling the vac hose off also does the same job. However this pipe must be blocked off also. This is what i did to the bmw and no issues. My vito does not have this fitted. Odd but very happy its not present. Ask a specialist what they can do to remove the EGR system. Leave the transducers fitted and connected to the wiring. This will prevent unwanted codes and errors forming in the computer. I do recommend to clean this type of unit regularly because of the carbon and soot with oil build up.

 

[mushr00m]

Hi, thanks for the information! I can get to 70 easily enough, just have to switch off/on ignition if light comes on! So if I pull the vacuum pipe off the EGR so it can't open, that should cause the engine to suffocate?

No you should not suffocate. the suffocation occurs when it opens allowing bypasses to enter main air system.

 

[mushr00m]

Side bypass = block off
Vac disconnect and block off rubber pipe.
Job done so to speak. make sure there are no leaks. This is how BMW do it. It is how i did mine. Side bypass is the recirc gases. yes i know its a bimmer but principle is the same.

 

[Danthevitoman]

Great info everyone, my vito gets to 80mph fine but will throw a yellow engine light if you plant the accelerator and try and power past. I'm going to try the transducer first and see if it works. I was told it maybe a NOX sensor in the exhaust by a friend that owns various expensive Mercedes cars and has experienced similar problems on the motorway. At least its nice to know its not just my old vito doing it, you don't escape the merc wows even if your loaded . my conclusion is just don't floor it, and don't try and go over 80. Fixed.Cheers drive safe.