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E350 CDI OM642. Lack of power and P0299 fault code.

ALFAitalia

MB Enthusiast
Joined
Feb 19, 2022
Messages
7,377
Location
Bognor Regis
Car
2010 Mercedes W212 E Class E350 CDI Sport, 2006 Mercedes W169 A Class A170.
Hi....as the title says........ it was driving fine yesterday .....but when I was nearly home I noticed a lack of power and she was holding onto gears for rather longer. This morning she was like that that from the off....feels like there is next to no boost at all. Before I have to go our (in the wife's A Class now!!) i had a quick look for lose hoses and vacuum pipes....nothing obvious but as you know its pretty packed under there!! The turbo vane actuator arm is working when I rev it....although I'm not sure how much it should move when revving in neutral. but at least it responds to the throttle. No obvious boost leak sounds when driving or revving and I can just here the turbo spooling up with the bonnet up and engine cover off. The only things that have happened recently is a new grille.....but I cant see anything that I might have knocked there....and also the PCV valve popped out of the batwing near the turbo exit.....now refitted and held in place with cable just to be sure....but the car ran fine after that. That's pretty much all the info I can give. P0299 (low turbo pressure) is the only fault found.....I reset it and so far its not come back....but still no boost so I'm sure it will return. Any info gratefully received....I've only had her a few weeks....not a great start after 5 years with no engine faults on a 175,000 mile ALFA!!!!
Thanks in advance.
 
Hi....as the title says........ it was driving fine yesterday .....but when I was nearly home I noticed a lack of power and she was holding onto gears for rather longer. This morning she was like that that from the off....feels like there is next to no boost at all. Before I have to go our (in the wife's A Class now!!) i had a quick look for lose hoses and vacuum pipes....nothing obvious but as you know its pretty packed under there!! The turbo vane actuator arm is working when I rev it....although I'm not sure how much it should move when revving in neutral. but at least it responds to the throttle. No obvious boost leak sounds when driving or revving and I can just here the turbo spooling up with the bonnet up and engine cover off. The only things that have happened recently is a new grille.....but I cant see anything that I might have knocked there....and also the PCV valve popped out of the batwing near the turbo exit.....now refitted and held in place with cable just to be sure....but the car ran fine after that. That's pretty much all the info I can give. P0299 (low turbo pressure) is the only fault found.....I reset it and so far its not come back....but still no boost so I'm sure it will return. Any info gratefully received....I've only had her a few weeks....not a great start after 5 years with no engine faults on a 175,000 mile ALFA!!!!
Thanks in advance.
I had similar symptoms on my E320 CDi. I had a faulty actuator which was replaced and improved things but also had a faulty exhaust back pressure sensor.

It may be worth removing the latter (just along from the EGR pipework from memory) and try to clean it with brake cleaner or similar?

I eventually replaced the sensor aswell (circa £50) which solved the problem 👍
 
fuse F44 covers the actuator, inlet port motor , exhaust back pressure sensor and egr . A fault in one can be hard to pin down.
Put a 4.k ohm resistor into the middle two terminals of the power supply to the inlet port motor (swirl flaps) ..cost £1
Spray clean the hole on the underside of the ebps , next to the turbo ..watch the chrome washer underneath it . 24mm deep socket .
Put some small amount of high temp grease on the worm gear inside the actuator ,after spray cleaning the carbon muck out with electrical cleaner.
Change F44 anyway .
If that doesn’t work , the ebps is £60 new , they don’t last forever .
Someone like Essex turbos does recon actuators , you don’t need a new turbo with it unless talking to a main dealer .
Try a can of spray turbo cleaner into the front of the turbo when the car is running .
Take the egr out and clean that as well
As the car is new to you and you are handy , I would do all of them.
Edit , the F44 fuse is the W211 facelift , not sure which one it is on the W212 engine ,even though it’s still an om642 .
 
Thanks gents..... no time off now until Friday.... so I will run through all of these then.....but if anyone else has any other ideas to add to the list that would be great.... the more things I have to try the more likely one of them will be the solution!
 
Looking back at my records I also replaced the engine boost pressure sensor. Each change from actuator then the two sensors brought incremental improvement and stability.

Boost pressure sensor part number was A0061539928
and may be the same for your engine.
 
Where is the boost pressure sensor on these... somewhere on the batwing?
 
Thanks... although I should not be such a lazy git and should have googled that myself!!!
 
Why bother buddy when you can get some other chump to do it for you :) (I’m busy drinking some port I found lurking upstairs after a cupboard clear out .)
No, you are diligently checking it is safe for use by dedicated organoleptic testing 👍👍
 
fuse F44 covers the actuator, inlet port motor , exhaust back pressure sensor and egr . A fault in one can be hard to pin down.
Put a 4.k ohm resistor into the middle two terminals of the power supply to the inlet port motor (swirl flaps) ..cost £1
Spray clean the hole on the underside of the ebps , next to the turbo ..watch the chrome washer underneath it . 24mm deep socket .
Put some small amount of high temp grease on the worm gear inside the actuator ,after spray cleaning the carbon muck out with electrical cleaner.
Change F44 anyway .
If that doesn’t work , the ebps is £60 new , they don’t last forever .
Someone like Essex turbos does recon actuators , you don’t need a new turbo with it unless talking to a main dealer .
Try a can of spray turbo cleaner into the front of the turbo when the car is running .
Take the egr out and clean that as well
As the car is new to you and you are handy , I would do all of them.
Edit , the F44 fuse is the W211 facelift , not sure which one it is on the W212 engine ,even though it’s still an om642 .
Just researching the resister mod. Many saying it will throw an EML on the 212 due to the ECU monitoring its opening and closing. Is this true?.... be useful to hear from 212 E350 CDI owners that have done it. Also do you need to manually position the flaps in a certain position first like you do with ALFA swirls... so they are fully open all the time.
 
Just researching the resister mod. Many saying it will throw an EML on the 212 due to the ECU monitoring its opening and closing. Is this true?.... be useful to hear from 212 E350 CDI owners that have done it. Also do you need to manually position the flaps in a certain position first like you do with ALFA swirls... so they are fully open all the time.
That’s a good question on the 212 , I don’t know is the best answer . But on the 211 , it’s a case of if the swirls are connected then they are open when the resistor is fixed in so it just tricks the inlet port motor to think it’s doing its job .
The inlet port motor which of course will have packed up because oil drips from the orange turbo seal which is above it .
In my defence I had copied and pasted my reply to you (because of the port drinking ) from another om642 thread :p .
It does seem to me after 12 years with the om642 and 100k+ miles that nearly all problems are , egr,swirl flap,inlet port , ebps and actuator which are all connected to the same fuse .
But all my suggestions are free to do so it’s not time wasted . I pretty much do the same as I have advised you on my car every 2-3 years as preventative maintenance.
 

Just researching the resister mod. Many saying it will throw an EML on the 212 due to the ECU monitoring its opening and closing. Is this true?.... be useful to hear from 212 E350 CDI owners that have done it. Also do you need to manually position the flaps in a certain position first like you do with ALFA swirls... so they are fully open all the time.
@MrGreedy do you know the answer to the resistor on the 212 ?
 
I didn't change my swirl flap motor during the oil cooler change, just cleaned it up and refitted as it was working fine until a few days ago.
My car is a c207 e350cdi 265 bhp. I didn't get an eml light on the dash but went into limp mode, no boost, plugged it in and it was the swirl flap motor. I have a bag of resistors luckily as I know it's a common fault and I'm currently running it with the resistor mod until I get time to replace it.
Personally I think the throttle response and general drive of the car is affected which is why I will be replacing it but I'm ocd and it does work to keep it out of limp mode.
 
I have a back up Merc and pick up truck... so I should be OK....:p
 

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