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Discussion Starter · #1 · (Edited)
I had recently message "check injection system" and with my cheap OBD2 reader it reads P0470 (exhaust pressure sensor). Engine is K9K 636 81 kW (110 HP). Sensor itself seems to be fine (cheched with voltmeter, 0,9 V and when I blow air into opening, voltage increases about 0,1 V).
It seem so me problem is clogged metal pipe below. There is no pressure comming out. I tried to clean it with guitar string on electric screwdriver, no successs. I even managed to break off some winding and now it is left inside the pipe.
Now, my question is how to remove entire assembly (with metal pipe), there is so little space behind the engine even to see where pipe ends.
??
 

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I've marked in red the path the pipe takes. You should have a rubber hose that connect to a thin metal pipe. My bet, the thin metal pipe is blocked and your string got caught in there.

189586
 

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Now, my question is how to remove entire assembly (with metal pipe), there is so little space behind the engine even to see where pipe ends.
??
You will have to get under the car to get at the back of the engine. I checked that pipe on my car today for you. How you got that sensor out of the rubber hose is beyond me. I tried for almost half an hour and gave up. I was keen to check if mine was clogged. But was unable to release the sensor from the hose. I did check how to get to the metal pipe though. If you go under your car, you can get a spanner on the nut as there's plenty of room from underneath, rear of the engine.
 

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Discussion Starter · #5 ·
I did try underneath, I went to my mechanic, he has access underneath, the DPF is in the way, no way...
I used carbuettor spray, it states that it removes carbon deposits and bicycle wire on a drill for some time. No success.
I will go to authorised service, I know exactly what is the problem and I will pay big fee...

...keep you posted...
 

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Super fantastic Mod Technical Supremo Nice Guy
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Subframe off Force engine forward, just enough room then
Its time consuming but not hard
 

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I did try underneath, I went to my mechanic, he has access underneath, the DPF is in the way, no way...
I used carbuettor spray, it states that it removes carbon deposits and bicycle wire on a drill for some time. No success.
I will go to authorised service, I know exactly what is the problem and I will pay big fee...

...keep you posted...
It's not the DPF in the way, it's the EGR cooler. But like Ours mentioned, push the engine forward and you'll have complete access.
 

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Super fantastic Mod Technical Supremo Nice Guy
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Subframe holds engine and gearbox up
But to have a fighting chance of sorting, without stripping half the engine then its subframe off
Might take a few hours to get subframe off , but would rather do that than strip/round off a bolt/nut.
Have seen and worked on too many cars where people have tried to save a few hours, and have ended up spending many hours putting the car right ,
Tip when working on a car engine, even with the best tool kit in the world.
IF IT'S in the way, remove it
 
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Listen to this man matey, he really does know what he’s talking about. He fixed a similar problem on my GS a couple of years ago and is the only bloke I’d want putting spanners on my car.

PM’d you btw Stu
 

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How far can you push the engine?
Subframe means rubber mounts ?
You have no choice in this scenario, other than to remove the rear subframe. You 100% need to get the wire out of the pipe because you go ahead an start your car. I know it's a bad situation. But that's what your here for right - advice on how to get to parts. If you know someone with a 4 post lift. Then maybe, just maybe, you'll be able to get to that bolt. I'm doing my timing belt this weekend. I'll take pictures of the part in question to give you an idea of what your dealing with.
 

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Discussion Starter · #14 ·
Authorized service told me it is sensor itself faulty, not the metal pipe. I dissagree with thar. He claims there is supposed to be no pressure in exhaust during idling. Sounds strange...
Anyway, I am still waiting for them to call me for final result....
 

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Authorized service told me it is sensor itself faulty, not the metal pipe. I dissagree with thar. He claims there is supposed to be no pressure in exhaust during idling. Sounds strange...
Anyway, I am still waiting for them to call me for final result....
How the hell did your mechanic determine the sensor at fault? If the pipe is blocked, how is the sensor suppose to operate? Keep us posted. Good luck.
 

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Discussion Starter · #16 · (Edited)
It turns out it is sensor malfunction. They replaced it, car works fine, no errors reported so far. I made some 10 miles.. I will know for sure in next few weeks...

I tested sensor myself :
0.88 V atmospheric pressure ..in between is linear... 5V at 6 bar
It seems OK, maybe too high pressure to reach full voltage

Anyway seems like a good lesson for me..
 

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Sorry to hijack your thread, But I had a similar problem today, but it turns out that my rubber hose that connects the sensor and the metal pipe ruptured.. burned through. Since the dealer sells the set (metal pipe+ rubber hose) for a ridiculous sum (100+ pounds), I tried to find an adequate hose, but to no avail. The hose is a standard high pressure fuel hose, but 6mm ID, and around 12mm OD.. So the hose is pretty meaty. I can't find a suitable replacement, so my mechanic took a 6mm hose, and stuffed it into a 12mm hose, so I got 6mm ID with thick sides for the rubber hose. 2 clamps.. and off I go. I thought the hose is some kind of silicone material, due to the high temperatures, but.. its normal reinforced hose. The heat from the ruptured hose melted a piece of my valve cap. Luckily just a tiny bit...

Why all the ramble.. does anybody know where to get a suitable replacement.. to have as a spare? Or do I have to keep this bodged solution, that looks even better than the original..?
190254
 

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Discussion Starter · #19 · (Edited)
Again I have the same 0470 error code. This time it's clogged pipe. Service people told me that. I am going to try oven cleaner, it might do the job.
Is there some other good solvent of soot to apply here?
What is the size of bolt that connects this pipe to exhaust manifold? 8 mm or 10 mm or ....?

Any thoughts?
 

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I tried with oven cleaner and it worked! I poured this liquid cleaner in the pipe and sccrubbrd it with plain guitar wire. I tried with bike brake cable, it did not work.
Suddenly fluid dissappeared down the pipe. I guess I clened it. Started the engine , drove few km , error was gone. It looks ok for now...
It will clogg again but now I know this really fast method to clean it.
 
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