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Hi stw,
Have tried the owners forums to no avail. OH has a petrol 1.8 xsara picasso that's throwing a P0403 fault code relating to egr control circuit failure. The valve is a single unit and electronically actuated, 5 pin plug no vac lines or separate solenoid.
Should I be able to hear the valve open and close with the aid of a screwdriver or wooden spoon? Need to check before replacing it.
Thanks
It'll go 'vwap vwap' when it operates, at least mine does.
However, the question is how are you planning on operating it? On my car (diesel Passat) when you start from cold it leave the valve closed then opens it after about 10-15 seconds of idling. You can hear the engine note change when it happens. Mine also defaults to closed, so if you unplug it it might spring closed if it were open to begin with.
However if you have a code saying 'control circuit failure' it seems a safe bet. If you disconnect it, you should get something like 'open circuit' which will prove that it is actually the control circuit and not the wiring etc. Try that first.
Its probably crudded up. Just de-gunk it and it'll probably be fine. Might be worth checking the hoses too, as they'll likely be bunged right up.
My car has 2 EGRs. One disconnected to plug the hole (blanking plates not available) and another connected in the engine bay to stop the engine warning light coming one, so the engine THINKS its working fine.
Its probably crudded up.
Probably not, since it's reported a control circuit failure. I'd say that's likely (but not certain of course) that the control circuit has failed. They DO gunk up depending on usage, yes, but that's not always the problem.
Do not fudge it. Car pollution is bad enough without people making their cars dirtier. And bigyinn's fudge wouldn't work on all cars, since mine measures (or rather implies) the EGR flow and will throw a code if it's out of range.
It depends. Linear egrs are difficult to test without a scan device capable of initiating an egr cycle. Some control units can measure the amount of egr movement and therefore will detect a lack of movement as a control failure. Some that don't measure the degree of movement will report a control failure even though it is a movement problem.
If you do a lot of idling, or little constant speed, constant load driving (the egr is only activated at less than around 15% load, at greater than 20mph, when running closed loop etc) then the egr sits umoving a lot of the time and will gunk up with carbon.
I am curious to know what you can do with a screw driver/wooden spoon on yours? If you can trigger the egr somehow and the engine slows and runs rough the valve is closing. If not it probably isn't. O
On linear egrs, if you don't have a scan tool and you don't want to pay a tech. then your only option is to remove it, visually/mechanically inspecting valve and if confirmed free to move reinstall. If code reoccurs it is the control, if it doesn't it was the valve.