p0235 turbo boost fault?

[glenandem]

hi guys, newbie here, ive got a vectra 04 3.0 v6 cdti that drives good but soon as i go on a mway or somewhere i can put my foot down the boost disapeers, so it must be going into safety mode, the spanner light is on the dash but no mil light?
ive read the ecu with a basic sealey code reader and im getting p0235 which was turbo boost circuit a malfunction or something like that but i cant remember the exact wording!
ive tried to clear the fault but without even driving it the spanner light comes straight back on?
im presuming its turbo either boosting too much or not enough so what areas should i look at and has anyone ever had this fault code?
any advice would be much appreciated!

[ghostdog]

Got this from TIS 2000, hope it gives you some pointers.
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With trouble code P1635 not recognised:
The boost pressure is too low
Effect:
Exhaust gas recirculation valve is switched off
Boost pressure control is not longer possible.
Concerned Terminals:
ECM: 87, 93, 98 (XC38)
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With trouble code P1635 not recognised:
The boost pressure is too high
Effect:
Exhaust gas recirculation valve is switched off
Boost pressure control is not longer possible.
Concerned Terminals:
ECM: 87, 93, 98 (XC38)
---------------------------------------------------------
Verify mechanical system functions/components
Check charge-air cooler for leakage.
Check the hose clamps at the intake-air system / charge-air system for correct fitting.
Check intake system/charge air hoses for leaks (secondary air, porosity and blockages)
Check connected hoses and tubes for kinks, damage etc.

[bobssignum]

DTI engine layout 2.jpgIMG_3206A.jpgIMG_3208A.jpgIMG_3211B.jpgpic 1.jpgpic 2.jpgpic 1001 vacuum hose.jpg
P0235 is related to your boost pressure sensor ,it may be something simple like the sensor just needs a clean or it may be that you have either split or perished intercooler hoses or possible split or broken vacuum tubing , both of these tube faults will cause the engine to go into limp mode and generate the p0235 fault code .
get some one to help you and while reving the engine listen for air escaping (whistling sound 0 or look for signs of oil seepege around the intercooler hoses
The above pics gives you a guide to what to look out for.
The above pics are of a 2.0 DTi lump but should be sufficent in this case

[glenandem]

Hi guys, spent this afternoon looking at the car and firstly it was due a service so changed all the filters and oil then got cracking on this fault, checked all vac pipes ok then checked turbo pipes all ok, next I decided to roadtest the car and as soon as i was cruising the car went straight in to safe mode so i cleared the faults and this time instead of the spanner light coming back on it stayed off so I absolutely nailed it down a bypass and revved the balls off and the smoke that poored out the back was crazy, after a few mins it was nice and clear but soon as I started cruising safe mode and spanner light so pulled over read ecu and p0409 egr circuit a, cleared it road tested and same code 3 times so presume its egr valve, gonna take it off and clean the valve up, can anyone tell me best way of removing the valve and do I need to take inlet manifold off?

[Celes]

To remove the EGR on this thing you need to use the force lol
In all seriousness it should take you 1.5h max to take the EGR out. You do need to remove the upper inlet manifold though

[glenandem]

To remove the EGR on this thing you need to use the force lol
In all seriousness it should take you 1.5h max to take the EGR out. You do need to remove the upper inlet manifold though

Cheers pal, looks well tucked away next to cambelt!
can you get away with cleaning these up or will it most likely want a replacement?

[bobssignum]

Egr valves suffer from a sticking piston which sits on a cam inside the plastic shield .
The egr is only retained by 2 bolts it also has two coolant hoses and an electric connection underneath .
The usual rules apply when removing the hose connection ie de pressure the system first and dont open when the engine is hot , Have a drill bit handy to plug the hose to stop the coolant leaking eveywhere .
The egr has an o ring which sits against the piston face and can be retained for reuse once removed it is easy to see the piston , then all you have to do is ensure that it moves freely , use carburettor cleaner to remove the carbon deposits .

[Celes]

I tried celaning mine but it was no use, it needed a replacement unit. I think I had the same fault code P0409 and massive black smoke.

[glenandem]

I tried celaning mine but it was no use, it needed a replacement unit. I think I had the same fault code P0409 and massive black smoke.

Cheers guys, gonna clean it up tomorrow night, do I need to get underneath the car then to get these bits underneath the egr or is it all work from the top of the engine?
also checking the car for mot found the drivers front coil spring missing a coil so got to sort that and need to get round to my heater switch problem only works on 4 which I believe I'd the green resister behind glovebox?
apart from that she's a beaut!

[Celes]

You don't need to get underneath the car mate but you will certainly break a sweat if you've never done this. It might seem easy until you get to the last bit which is the bolt that's holding the clamp to the EGR cooler. You can get to the bolt without removing the fuel rail sensor and you can't remove the fuel rail sensor without removing the bolt haha. With the right tool and patience you can do it though. Good luck.