c5 turbo cut out

cachaciero · Post by **cachaciero** » 06 Apr 2010, 11:56

The following ids from part of a thread in May 2009
There were several other threads roundabout this time that touched upon this.

PostPosted: Tue May 05, 2009 10:01 pm Post subject: How to Check the Turbo and Swirl Valve control C5 2.2. HDI Reply with quote
corsehf wrote:

cachaciero,
is it possible to post or PM me any instructions or pics so that i can check my diaphragm personally. In the mean time, i will do that other check that you mentioned.

Hi corsehf

Hope that this helps Smile

INTRO

The proper way of checking this system really requires a vac gauge and ideally a vac pump. Gunson do a vac gauge for about £20.00 guess this would probably do ideally you need a calibration in Milli Bars saves having to do conversions.
Getting the swirl valve diaphragm out just to look at it is a pig of a job and dismantling the swirl valve actuator to look at the diaphragm risks breaking the actuator as it is not designed to be dismantled.

SYSTEM DESCRIPTION

The turbo turbine is modulated by a diaphragm type actuator mounted on the Turbo,
this diaphragm connects to a piece of hard plastic pipe using a silicon rubber coupler. The plastic pipe runs upstairs to the turbo electrovalve (RH side looking in from front under the scuttle panel adjacent to suspension sphere ) where another rubber coupler connects it to the valve. Other side of this EV runs to the vacuum reservoir which is under the brake servo.
This vacuum reservoir is common to the swirl valve system and is fed from the engine driven vac pump through a small restrictor. There is a plastic pipe which runs forward from the reservoir to the swirl valve electrovalve (EV) to which it is connected on the top by a piece of curved silicon tubing. The supply from the side of the EV runs back to the swirl valve actuator hidden underneath the air ducting and the EGR pipe.

TEST PROCEDURE

To test the system a vac gauge needs to be connected into the system, I used some small plastic hose couplers purchased from B&Q and piece of suitable sized plastic pipe.
Removing the coupler on the TOP of the swirl valve EV connect a T piece into the silicon elbow a short length of pipe from the T piece to the top of the EV the other arm of the T piece is connected to the vac gauge.

Run the engine with a good system the gauge should fall to about 200 mBars absolute at idle anything more than this and there is a leak.

Lets assume a vacuum of 800mBars i.e a leaking system, disconnect the plastic pipe from the top of the EV and place your finger over the open end of the pipe if the vacuum now increases to 200 mBars then this would indicate a leak between the EV and the swirl diaphragm and /or the diaphragm itself.
To eliminate a problem with the EV connect the pipe that comes out of the side of the EV directly to the piece of plastic piping attached to the T piece and check the vac levels again if values still high then the only thing left is the swirl diaphragm AND the rubber connector that connects the plastic pipe to it.
I have assumed that the plastic pipe is relatively bulet proof and that it is unlikely that this will leak.

If this does not change the vacuum then the leak is likely on the turbo side, again the same procedure can be used breaking the system down at the T urbo EV and inserting the T piece and vac gauge.

With good vacuum the operation of the Turbo diaphragm may be checked by linking the vac input to the EV directly to the output to the turbo doing this you can observe the operation of the actuator from underneath the car.

If it is shown that the system is leaking then the first thing to check are the associated rubber pipe couplers. There is quite a bit of documented evidence that splitting of these rubber joiners is quite common so it pays to check them carefully. In my case not only did I have five holes in the swirl diaphragm but the rubber connector to the assembly was also split.

I would suggest that a couple or three of these rubber couplers are on hand before starting the exercise.

Changing the swirl valve diaphragm.

This requires removal of thefollowing:-

1 air filter box (top). (To gain access )
2 EGR pipe approx 1 inch dia stainles pipe that runs from back of engine to inlet manifold.
3 Breather pipe1 inch approx that goes into the head.
4 metal bracket that support pipe work (EGR pipe) (will lose a little water when removing this)

This will give access to the three TorqX screws that hold the swirl actuator in, they can be reached with a T20 bit on a long extension bar. Diaphragm re-moved and re-fitted from underneath. Car needs to be on ramps or axle stands.

Materials
1 Jubilee clip to replace clip on breather system.
2 Manacle clamp for coupling EGR pipe to water jacket at back of engine this is a service part as the old clamp will not be re-usable.
3 Diaphragm.
4 Suggest a couple of spare screws as they are quite easy to lose.

Cachaciero

sijrayner · Post by **sijrayner** » 06 Apr 2010, 13:33

tks again for the help. i am so out of date with mechanics. i need to locate some pics of the various bits i am trying to check. i had never heard of a swirl valve or any of the other bits, hence my need for a manual so i have pics of things to identify. been looking at peugeot sites etc for pics of where these parts are on the 2.2hdi.

KevMayer · Post by **KevMayer** » 07 Apr 2010, 00:33

I believe the fault is with the wiring to the vacuum solenoid.

The ECU will monitor the supply to this solenoid. If it fails to communicate with it, i.e. no current flows to the solenoid (open circuit) or too much current flows (short circuit), then the ECU will flag the error 'turbo circuit open/short'.

Fuse 15 in the engine compartment fuse board supplies the turbo vacuum solenoid, it also supplies the EGR vacuum solenoid and the swirl valve vacuum solenoid.

You can either check fuse 15 directly or just rev the engine to above 2100 rpm and observe the arm on the swirl valve control to see if it operates.

The arm on the swirl valve is on the right hand end of the engine (when looking towards the engine from infront of the car) on the top of the engine.

Best of luck.

sijrayner · Post by **sijrayner** » 07 Apr 2010, 08:29

is that arm the one which looks like an old fashioned throttle arm with a black plastic ball joint on the end ? if i rev to over 2100 it should move.

KevMayer · Post by **KevMayer** » 07 Apr 2010, 09:15

That's right. It operates to open the swirl valves.

Have a look at this link to see how the swirl valves work:-

http://www.citroenet.org.uk/passenger-c ... tech3.html

cachaciero · Post by **cachaciero** » 07 Apr 2010, 10:22

KevMayer wrote:I believe the fault is with the wiring to the vacuum solenoid.

You may be right but I doubt it.

The ECU will monitor the supply to this solenoid. If it fails to communicate with it, i.e. no current flows to the solenoid (open circuit) or too much current flows (short circuit), then the ECU will flag the error 'turbo circuit open/short'.

Correct but this is not the same as Turbo Overboost which is as I understand it what the diagnostic said.

Fuse 15 in the engine compartment fuse board supplies the turbo vacuum solenoid, it also supplies the EGR vacuum solenoid and the swirl valve vacuum solenoid.

You can either check fuse 15 directly or just rev the engine to above 2100 rpm and observe the arm on the swirl valve control to see if it operates.

The fact that the swirl valve appears to operate should NOT be taken to mean that the vacuum system is good. One of the reasons why this problem appears to be so inconsistent when it happens on the road is because if as is often the case the diaphragm itself has splits along it's fold lines as the diaphragm moves so the splits open or close depending, with resultant loss in vacuum this will often affect not only the ultimate position of the swirl arm but also the amount of vacuum available to modulate the turbo. With this problem I cannot over emphasise CHECK THE VACUUM FIRST it's not difficult

The arm on the swirl valve is on the right hand end of the engine (when looking towards the engine from infront of the car) on the top of the engine.

Best of luck.

cachaciero

sijrayner · Post by **sijrayner** » 07 Apr 2010, 10:42

tks gents, i will report back.

KevMayer · Post by **KevMayer** » 07 Apr 2010, 18:49

Hello cachaciero.

My idea of looking at the electrical side of things is because in the first post sijrayner reported that the Lexia gave an error message which said "turbo circuit short/open". It didn't report an overboost as far as I can tell.

The ESP/ASR warning came up on the dash, and so it would if the solenoid was not working because, as you rightly point out, there would have been an overboost. But, unless sijrayner could confirm for us, we aren't told of an overboost alarm reported by the Lexia.

If the solenoid isn't working then an overboost would result. I agree with this point. All I'm trying to say is that the alarm of 'turbo circuit short/open' is pointing to an electrical control problem which will be different to a pure overboost due to a split diaphragm.

The information I have shows that the turbo boost control is a simple closed loop system. The vacuum solenoid is the control actuator and the pressure sensor, on top of the intercooler, provides the measurement feedback signal.

The 'turbo circuit' would probably include both the solenoid and the pressure sensor, so, if investigation of the vaccum solenoid doesn't reveal anything then the fault could be with the pressure sensor.

Do you have any other idea of what Lexia alarm 'turbo circuit short/open' could mean?

I'm certainly learning more about my C5 through discussions like this. I'm not an expert by any means, I'm not even in the trade, I'm just a very keen enthusiast

cachaciero · Post by **cachaciero** » 07 Apr 2010, 22:44

KevMayer wrote:Hello cachaciero.

My idea of looking at the electrical side of things is because in the first post sijrayner reported that the Lexia gave an error message which said "turbo circuit short/open". It didn't report an overboost as far as I can tell.

Um....... you are correct, I guess I saw what I wanted to see

however I think that I would like to ask the man again, in my experience (limited) many mechanics arn't always clear about what they are seeing or very clear in their explanations.

The ESP/ASR warning came up on the dash, and so it would if the solenoid was not working because, as you rightly point out, there would have been an overboost. But, unless sijrayner could confirm for us, we aren't told of an overboost alarm reported by the Lexia.

If the solenoid isn't working then an overboost would result. I agree with this point. All I'm trying to say is that the alarm of 'turbo circuit short/open' is pointing to an electrical control problem which will be different to a pure overboost due to a split diaphragm.

The ESP/ASR warning will come up with Turbo Overboost too.
The ESP/ASR system relies on data from the engine ECU if that data is not available either because the data is not there or because the data bus is down then the system will fail and it will post the ESP/ASR message. I believe that any engine ECU failure that puts it into LIMP mode will cause ESP /ASR failure.
The rest of your logic is pretty good

but followed through to it's logical conclusion if the solenoid isn't working and the ECU detects that I wouldn't expect that to put the engine into LIMP mode UNTIL the turbo pressure reached an overboost condition at that point it would go into LIMP mode. I would then expect the Lexia to show both a solenoid / EV error AND a Turbo Overboost error.

The information I have shows that the turbo boost control is a simple closed loop system. The vacuum solenoid is the control actuator and the pressure sensor, on top of the intercooler, provides the measurement feedback signal.

The 'turbo circuit' would probably include both the solenoid and the pressure sensor, so, if investigation of the vaccum solenoid doesn't reveal anything then the fault could be with the pressure sensor.

Do you have any other idea of what Lexia alarm 'turbo circuit short/open' could mean?

My understanding is also as you describe it although there are some areas of the engine operating regime when the turbo is run "open loop"
Your right saying that the problem could be the sensor but if the sensor is U/S that should easily be seen on the Lexia, if the flow rate was outside of the MAP based upon engine RPM throttle position etc it would post an error and the actual flow can be read from the Lexia.

My understanding of that lexia message Turbo Circuit Short / Open would be the same as yours, the switching device in the ECU will have the ability to detect both an open circuit and a short circuit and set a logic line to the ECU computer there is no way that the ECU computer can tell which of the two conditions exist hence the form of the message.

I'm certainly learning more about my C5 through discussions like this. I'm not an expert by any means, I'm not even in the trade, I'm just a very keen enthusiast

That makes two of us

I purchased mine just over a year ago and most of my reading since then seems to have been C5 technical related

.

It would certainly be interesting to know for sure that the lexia message was Turbo Circuit short/open but then I would expect to see a Turbo Overboost message as well. Logically I would not expect low turbo pressure to put the engine into LIMP mode but overpressure certainly.

So far the Turbo EV has been changed with no improvement yes it is possible that there is an open circuit from the ECU to the EV but I would put it low down on my scale of things to check first.

I would treat the the Turbo Solenoid message with caution simply because we don't know when it got posted it could have been in the ECU for years. If anybody at anytime prior to the ECU being read disconnected the EV, trying to troubleshoot this problem maybe, with the ECU up and running that message would get latched into the ECU until the next time it was cleared with a Lexia.

Ideally one would connect a Lexia up clear the fault codes go for a drive until the problem re-occurs and THEN read the fault code.
However given that that is probably an expensive option I would still concentrate on proving that all is good on the vacuum side it is about five minutes work to isolate the swirl valve from the vacuum system, an isolated swirl system will not bring up any errors and the car is quite drivable it's a quick way of provoking some change maybe even a temporary cure of the problem.

cachaciero

sijrayner · Post by **sijrayner** » 08 Apr 2010, 08:23

Ideally one would connect a Lexia up clear the fault codes go for a drive until the problem re-occurs and THEN read the fault code.

just to clarify the situation, i went to mr citroen in south london. he set up the diagnostic check and ran it, then cleared all the faults and drove the car. the usual anti pollution fault came up (he said that is to be expected on a car of that age and mileage as the Eolys tank will be empty and it is not so important to pay £700 to refill and reset the ecu). the most important fault and the one causing all the probs came up as "turbo pressure fault/open or short circuit"
i will observe the swirl valve actuating arm at below and above 2100 rpm this evening. i shall try to do it when the warning is off and again when it comes on. are the fuses in the 'electronic' box behind the battery in the engine compartment ? i will check that as well.

cachaciero · Post by **cachaciero** » 08 Apr 2010, 10:14

Mr Citroen needs to go back to school

but at least he was logical in his use of the Lexia.

The Anti Pollution fault 99% of the time is nothing to do with the FAP .

The Anti Pollution message will come up for any engine malfunction which could cause the engine to produce more pollutants than it should and that covers most any engine / sensor related failure. This is an EC requirement.

In addition if the failure is such that if it could damage the engine the ECU reverts to a regime which will prevent engine damage so called LIMP mode, in the case of the 2.2 revs are limited to about 2500.

The only failure of the FAP system that is likely to provoke this scenario is when the filter gets choked to the point of creating substantial back pressure. Prior to this the FAP subsystem will likely bring up an equally confusing message Diesel Filter Blocked (or maybe Particle Filter Blocked)

Low Eolys levels will bring up a specific message to this effect i.e Low Diesel Additive. (according to the Bosch documentation havn't seen it myself). If Mr Citroen was using a Lexia he should have been able to read the Additive ECU and determine the amount of Eolys in the tank.

My recollection when i had this problem was that the message was quite specific i.e Turbo Overboost (or maybe Turbo Overpressure it's a while ago). I wonder if Mr Citroen was using a Lexia or some other device.

Anyway this is a little academic in that without doubt you have a Turbo Pressure problem, if the engine is going into LIMP mode than it will be overpressure, by far away the most likely cause for this is failure in the vacuum system that controls the Turbo.

cachaciero

sijrayner · Post by **sijrayner** » 08 Apr 2010, 11:52

hi, regarding which diagnostic system, tbh i asked if he had lexia, he said " yes i have a system ". as i work in tunbridge wells is there someone you would recommend down here with a lexia and if nothing comes of this weekends work i will go to a proper machine.

cachaciero · Post by **cachaciero** » 08 Apr 2010, 13:22

sijrayner wrote:hi, regarding which diagnostic system, tbh i asked if he had lexia, he said " yes i have a system ". as i work in tunbridge wells is there someone you would recommend down here with a lexia and if nothing comes of this weekends work i will go to a proper machine.

Well citronut who posts in this forum on a regular basis has a garage in East Sussex somewhere. Failing that I'm not so far from Tunbridge Wells if you park it somewhere where it is possible to work around the bonnet area I guess I could come over either lunch time or at the end of the working day and have a look at it, need about 2 hrs to check with Lexia and vac check.

If interested PM me.

cachaciero

sijrayner · Post by **sijrayner** » 08 Apr 2010, 18:37

ok just got home, update. i had my (not so willing) assistant rev the car to over 2500rpm while i stood and waited for some movement of the swirl valve actuating arm. nothing doing on that front at all. i checked the fuse in the engine bay and #15 fuse looks fine. i think i may have to go under the car to get a look at the bits i cannot get to from above, ie anything at the back.

cachaciero · Post by **cachaciero** » 08 Apr 2010, 18:58

Hi Simon

Plse resend yr mobile number the one you gave me doesn't get to you.

If you feel like doing some work on it this evening do this:-

Now you know where the swirl valve arm is

Remove the large diameter rubber pipe that connects the Air cleaner / Mass flow sensor to the plastic duct at the rear two jubille clips.

With this out of the way look at the swirl valve arm and then look down, on the side of the engine you will see an electro valve with a curved rubber pipe on connecting to a small diameter black plastic pipe. Take the rubber sleeve of of the electrovalve, at this point you should have a length of black plastic pipe with a 90 degree rubber sleeve on it hanging in the breeze. Now find something solid a bit of wood. plastic or even a suitable size bolt that you can stuff into the open end of the rubber sleeve, this needs to be tight enough to stop air getting in but not so rough it will tear the rubber. Now loosely secure the sleeve and pipe so that it can't flap around too much. Replace the rubber pipe connecting the air cleaner to rear plastic ducting.

Remove the black plastic coupling from the swirl valve arm this arm will now rotate rearwards freely secure in the rearward position ( closed) using a tyewrap bit of wire or string.

This should take you no more than thirty minutes.

Go and drive the car for a couple of days and report back.

cachaciero