Technical 2009 multipla multijet

[domdare]

Hi,
Hoping someone can help with an ongoing problem with engine management light and P0401 code.
Case history :
3 weeks ago car was in limp mode, no power in low range. Since then egr valve has been removed and cleaned thoroughly. Engine is running sweet as a nut now, but will the eml stay off ?! No it won't even after being reset a couple of times !
So my question is, could there be another issue, is the valve the culprit (P0401 code) is always the one that appears ? Does the MAF sensor has a separate code, if not, could it be the MAF.
Girlfriend doesn't want to blank it off, car has only done 26k, lots of short school runs !
Any advice greatly appreciated.

 

[jayc50000]

P0401 is an egr fault code but the airmass could bring that fault on.
Although you have cleaned the egr the fault will be in the electronic side of it. If the valve will not fully open or close it will put the light on. Blanking it off will still give you the warning light as the valve is faulty. Only way around it is to replace it.

 

[Most Easterly Pandas]

Could also be wiring, fault code only says there is an issue somewhere with the input into the ECU, may not be a faulty sensor.

 

[jayc50000]

The only input to the ecu would be a controller for the airmass or that's it's not gelling a return signal from the egr valves solenoid.

 

[domdare]

The only input to the ecu would be a controller for the airmass or that's it's not gelling a return signal from the egr valves solenoid.

Wondering if you know how far the valve on the egr should be open when its fully activated. e.g. Valve comes out about 10mm from body ? (as I have a feeling it may be stuck in closed position) Also, can the valve be opened manually by pushing the spring with long nose pliers ?

 

[jayc50000]

It's not how far you can push it out that matters it's how far the solenoid can open it. It needs to be able to reach it's minimum and maximum stop. If the solenoid is weak it can't achieve this.

 

[domdare]

It's not how far you can push it out that matters it's how far the solenoid can open it. It needs to be able to reach it's minimum and maximum stop. If the solenoid is weak it can't achieve this.

Hmmm, ok. And the other day when I took it off and cleaned it, I forgot to separate solenoid body from egr. Whats the betting its all gunged up in there too ?! Poor oversight on my part!

 

[domdare]

If I were to remove egr and separate two halves would I be able to test solenoid by plugging it back in and starting engine, or does that only work when egr is one sealed unit ?

 

[widemouthfrog]

There must be a contact made within the EGR - that would be how the ECU is informed that the EGR is operational. I'd guess that it will be a simple make/break electrical (as opposed to electronic) connection as it's in a pretty aggressive environment.

If the above is true, would it not be worth removing the EGR, put a multimeter across the pins (can't remember how many there are, but it wouldn't take long to work out which is which) then manually 'throw' the solenoid to see if you get a closed circuit? As jayc says it may be the solenoid not giving full travel, so you could try putting voltage across the coil as well as the multimeter on the other pins.

 

[jayc50000]

Yeah normally gets pretty gummed up in both sides.

 

[domdare]

There must be a contact made within the EGR - that would be how the ECU is informed that the EGR is operational. I'd guess that it will be a simple make/break electrical (as opposed to electronic) connection as it's in a pretty aggressive environment.

If the above is true, would it not be worth removing the EGR, put a multimeter across the pins (can't remember how many there are, but it wouldn't take long to work out which is which) then manually 'throw' the solenoid to see if you get a closed circuit? As jayc says it may be the solenoid not giving full travel, so you could try putting voltage across the coil as well as the multimeter on the other pins.

Oh, I feel a bit out of my league now, not great on electronics !
How do I put voltage across the coil?

 

[widemouthfrog]

It's electrics, not electronics in this case, and fairly basic at that. Have you got a multimeter, or failing that something like a brake light bulb and some bits of household flex?

 

[domdare]

Thanks for all the advice guys.
Going to give egr another clean, this time on solenoid side too, see how much travel there is manually ( not got any multiecu kit). If that doesn't work then Im just going to fit a new one.

 

[domdare]

It's electrics, not electronics in this case, and fairly basic at that. Have you got a multimeter, or failing that something like a brake light bulb and some bits of household flex?

yes I have bulb and some flex. No multimeter unfortunately.

 

[widemouthfrog]

This piccy shows mine when I cleaned it out a few years ago (yuk!). It's split into the solenoid (on the left) and valve sections.



You'll need to look inside the black connector shroud at the back end of the solenoid and see how many terminals there are. Then try various pairings of pins with the multimeter (or the bulb with some flex taped to the contacts and a small battery as well) while moving the solenoid pin by hand to see if you can get the circuit to make.

 

[domdare]

This piccy shows mine when I cleaned it out a few years ago (yuk!). It's split into the solenoid (on the left) and valve sections.



You'll need to look inside the black connector shroud at the back end of the solenoid and see how many terminals there are. Then try various pairings of pins with the multimeter (or the bulb with some flex taped to the contacts and a small battery as well) while moving the solenoid pin by hand to see if you can get the circuit to make.

Ok, when you say small battery, would aa suffice ?

 

[widemouthfrog]

Yes, but use a small bulb (e.g. one out of a torch) instead of a car bulb or you won't it light up.

If you strip back the flex at both ends to give you a brown and blue wire (or similar), the circuit you'll need to make will go:

Battery +ve > brown flex > one of the pins on the solenoid (you'll have to hold it in place with your fingers, but it's only 1.5V). Then blue wire onto one of the other solenoid pins and hold other end of blue wire against the side of the bulb and the bottom of the bulb on battery -ve. You might need your girlfriend to hold some of the wires in place, or use sellotape and tell her she's redundant .

With all that in place, try pulling/pushing the solenoid centre pin and see if the bulb lights up. Try all permutations of pin connections on the back of the solenoid and also try the metal body of the solenoid body - it's possible that the return path to the ECU uses this as one of the 'wires'.

 

[domdare]

Yes, but use a small bulb (e.g. one out of a torch) instead of a car bulb or you won't it light up.

If you strip back the flex at both ends to give you a brown and blue wire (or similar), the circuit you'll need to make will go:

Battery +ve > brown flex > one of the pins on the solenoid (you'll have to hold it in place with your fingers, but it's only 1.5V). Then blue wire onto one of the other solenoid pins and hold other end of blue wire against the side of the bulb and the bottom of the bulb on battery -ve. You might need your girlfriend to hold some of the wires in place, or use sellotape and tell her she's redundant .

With all that in place, try pulling/pushing the solenoid centre pin and see if the bulb lights up. Try all permutations of pin connections on the back of the solenoid and also try the metal body of the solenoid body - it's possible that the return path to the ECU uses this as one of the 'wires'.

Great info widemouthfrog, thank you !
I'll give it a go... and if girlfriend isn't required, I can always get her to bring me a nice cup of tea !! ;-)

 

[widemouthfrog]

Btw, this is the same solenoid after I'd cleaned it out. One of the aerosol brake cleaners with a long thin tube on the nozzle cleans it out a treat.



Anyway, back on topic. Larking about with battery, bulb and flex in the above manner will only prove whether the signal back to the ECU works (if indeed that is how the ECU is kept informed - if there's only 2 pins in that connector, I'd have my doubts). As jayc says the other thing you need to do is prove that the solenoid itself is capable of actuating the EGR valve. You'll need a battery changer or some jump leads to do that, and excercise a bit more caution as you'll be using a beefy 12V.

 

[domdare]

Btw, this is the same solenoid after I'd cleaned it out. One of the aerosol brake cleaners with a long thin tube on the nozzle cleans it out a treat.



Anyway, back on topic. Larking about with battery, bulb and flex in the above manner will only prove whether the signal back to the ECU works (if indeed that is how the ECU is kept informed - if there's only 2 pins in that connector, I'd have my doubts). As jayc says the other thing you need to do is prove that the solenoid itself is capable of actuating the EGR valve. You'll need a battery changer or some jump leads to do that, and excercise a bit more caution as you'll be using a beefy 12V.

Thats what id really like to do... see if solenoid pin moves properly under current !
Can I stil use flex with 12V battery method and could I damage unit if I connect to wrong terminals ?