Ds3 air con

Thanks David, looks like really helpful information however I still have questions. Is there anyway we can speak on the phone?
Are MC10, 35 and ecu modules or the earth points you have mentioned?

Is there a shop or someone like yourself you can recommend that know what they are doing with these cars? I have done the right thing by researching, taking the car to reputable shops, have swapped parts relating to the fault codes and i am no where near a solution....I am at a loss at this point...
 
It is a bit hard to recommend a local mechanic when you state your location as Australia on a Forum that is called Aussiefrogs.

Perhaps a more localised location might help us make some recommendations. As you are finding electrical problems are the most difficult of faults to troubleshoot and the wreckers are littered with cars these days that look perfect but have electronic issues that no one can solve because of the way the electronics in the modern cars interact.

Regards, Ken
 
You want to avoid taking it from workshop to workshop if at all possible. You've dealt with a dealer already and you'd need to go back to a dealer if it wants a BSI update - they would need both keys. If I am reading correctly you still have P0598 and P0599 faults, so you need to prioritise those. The thermostat housing should be 9808647080 and it may require the extra harness 9804315380 if the wiring didn't already suit the new thermostat housing. There are multiple thermostat housings for this engine family. Is this what you bought?

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Will the BSI update fix the issue with the air con?
The wiring is the correct one.
The dealer quoted me almost 5K to replace the thermostat, turbo cooling pump. There were changed outside of the dealer, the alarms could not be cleared and have not come closer to resolving the issue. I am starting to loose faith with the dealer, that was the reason I looked elsewhere.
 
I replaced an EP6DT turbo cooling pump recently, From memory about $220 for OEM and much less than an hours work. You can get a thermostat and housing for about $275 and say two hours at worst because of the extra stuff to get out of the way. Plus new coolant.
 
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The BSI update may be helpful, but if you have other engine related faults, address those first. Which faults keep coming back? P0598 and P0599. Others?
 
Hi David and Seasink, yes the parts where bought and changed at normal prices as you have indicated... it doesn't however detract from what a rip off prices i was quoted and no responsibility taken by the dealer.
I am still having the same codes active, and not able to reset, P0598 and P0599. There are no other codes present and the only noticeable with the car is the aircon not working... other than that's its a fun car to drive.
 
Both faults are no signal on the thermostat control line 1570, which comes without any branching direct from the engine ECU, pin 49 to the thermostat, item 1380. The brown connection with 53 pins.
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Is 1570 showing on this diagram? Can I test either 1380 or 1570 to ensure the ecu output is working?
Is it a fixed voltage out I.e. 12v or is it variable?
Does the ECU switch a ground signal and the 12v is coming from a fuse or are both controlled from the ecu?
 
For most functions the ECU switches the control line to ground, in a pulsed fashion, so a square wave form results. It is usually the pulse period that does the job.

Power comes from the ECU, pin 17 (1355), and serves both the VVT solenoid pin 2 (1355A), and the thermostat (1355B). Ie, there is a junction before both devices, the conductor dividing into A and B..

A comment in one of my blurbs is (RCO = Rapport Cyclique d'Ouverture):
La particularité de ce système tient dans le fait que le thermostat dispose d’une résistance commandé en RCO par le CMM. Cela permet de chauffer l’eau dans le thermostat et donc d’ouvrir le thermostat avant la température prévue si les conditions de roulage le nécessitent.

That is:
The particular feature of this system is that the thermostat has a resistance operated pulsed by the ECU. This allows the water to be heated in the thermostat and so open the thermostat before the normal temperature if driving conditions need it.

That would suggest it is a feature of a driving load during the warm up phase.
 
AC being deactivated is a direct result of both these fault codes. P0598 is short to earth while P0599 is to +ve and list common possible root causes are listed as engine ECU, harness or thermostat. P0597 is open circuit in the thermostat, but you don't have that.

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This may help with what seasink posted. You won't have the 4 way connector with the adapter / splitter harness at the thermostat. Wires are:
401 Coolant temp signal
1357 Coolant temp earth
1570 Thermostat control line. I expect this will be to earth when enabled.
1582B / 1042 via harness crimp 135 - supply to thermostat (This also supplies pin 1 of the coolant pump controller via a branch from crimp 135. If that works the supply should be working OK)
Is there end-to-end continuity from wires 1042 through 1582B and on 1570 ? Are any of them shorted to earth because of damage or a rub through - use multimeter.

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That's some good info... I will check continuity from pin to pin however as the pump is also not working, or at least I can't here it when the engine is off, I have a feeling it may be the ECU.
Are the ECUs repairable?
On a side note, does the thermostat housing and coolant pump downgrade anything else or just the air con, I.e. ignition timing, boost etc.
 
It's not the turbo cooling pump involved here. The main coolant pump is on the same circuit, but I think you should see 12V supplied to the thermostat and that pump with the ignition on. The earth is then switched as needed.
Usually also cruise control drops out, but possibly performance will be altered by the engine ECU.
 
There is a 3rd code P2602 which I believe it points to the turbo electric water pump.
I get approx 7v from the thermostat between the 2 pins or 1 pin + chassis earth... so it seams I am getting a constant earth and a low voltage... wirring harness is confirmed good.... look like ecu then....
 
P2602

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Coolant pump connection to engine ECU. 1580 is turbo cooling pump supply. 1581 appears to be earth / control. 1257 is apparently EGR control electrovalve earth and it may just be a convenient place to put it. The ECU circuit for this pump is supplied by F21.
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Power supply PSF1 fuses that feed the engine ECU are:
F1 - main ECU supply fuse.
F5 via R2 (I've marked F6 in the fuse diagrams below in error. Should be F5)
F19 via R2
F10 via R2
F20 via R2
F21 via R1

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Connection of PSF1 (engine slave fuse/relay box) and engine ECU. F20 appears to be the most relevant to your problem. It supplies Pin 6 of the black connector on the engine ECU. R1 is the main relay here and cascades to R2. Both R1 and R2 must be working as the car runs and that requires power to fuse F10 and others. Failure of F20 or the wiring to the engine ECU could explain the symptoms.


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