Ds3 air con

The turbo coolant pump uses engine bay F21 if I remember right.

The main engine coolant pump is driven by a friction wheel mounted on the end of the engine. It is disengaged at cold start. When cooling is needed it is wedged between the pump friction wheel and the back of the accessory belt.
 
That's an interesting method to control temp. I guess it also reduces pump wear.

Specifically to P0598 and 599, do you know if they are related to the main and or turbo pump codes or the thermostat housing?

I ve read that the thermostat fails and in turn the aircon is disabled in these cases. Thermostat failures seem to be common from other Google searches I ve done however I d like to think there are ways to test abd confirm prior to pulling everything apart. Do you have any information or knowledge on this?
Thanks again for all your help.
 
As already mentioned, the additional electric coolant pump for the turbo seems most likely.

My aircon failed inside 3 yrs. Electric coolant pump replaced under warranty and no issues since. It seems a common enough issue on THP engines.

P0598 and P0599 are faults with the controlled thermostat - short to earth and short to positive.
 
I mentioned it earlier, with pin details.

The thermostat housing faults are the "pilot" heater. The first error is the power, the second is the command line. No signals. Are you sure it's plugged in?

There are two plugs. On top near the bleed screw is the temperature sensor. The main connection is on the front face pointing rearwards.

The temp sensor works by variable resistance. It is around 1000 ohms at ambient temperatures, dropping to half that at 120 degrees.
 
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Also check wiring not burnt/melted as another common issue and I've seen many dodgy mechanics with crimp connector extension wiring added which all break down with the heat from turbo being nearby.
 
Thanks guys, will have a better look tomorrow.
To confirm, the electric pump and the thermostat mentioned above, are they on the turbo or on the engine side?
 
Electric pump is under the turbo, thermostat is at the end of head on gearbox side. Front sensor wiring usually visible once turbo intake removed. Do this while engine cold
 
Look underneath the oil filter. It is mounted on an odd shaped bracket inserted into the turbo coolant circuit. It uses a very simple motor. In a DS3 replacement if necessary is easiest from above with the air stuff removed as for a filter change.

turbo pump.png
 
Hey guys, I have checked things out again... everything was found to be plugged in and in good condition.
I am getting a constant ground signal at the thermostat housing but no 12v supply. Should there be 12v supply and ground is the control signal?
 
Pin 1 is a power feed. Pin 2 is the command from the engine ECU, and like most ECU commands is pulsed.

thermo.png

Not necessarily DS3 numbering
 
Understood, is that relay accessible and should I then be seeing 12v on pin1 with Ign on or engine running?
 
Hi all, just an update.
I ended up taking it to the dealership for diagnostics. They couldn't really isolate the issue with the air con but they did say that due to other faults, the air con doesn't not work.
The other faults are Engine thermostat, Turbo coolant pump and the turbo intake pipe ( there was a crack in it).
I baught all the above parts, just finished swapping them out and nothing.
The clutch on the air con is still not engaging, all the faults are still there.
Any ideas would be appreciated. Thanks.
 
You will need to have the faults cleared for them to go away. I've also heard that they become inactive after 20 -50 engine starts.

Cheers, Ken
 
AC and cruise are often disabled as a downgrade mode when there are other faults. Erase the faults, drive it and read again. A common reason for no AC is the engine fan control module failing and you may see fan control faults such as P0493 or 494. The compressor clutch coil can also short out, but I think you may have eliminated that along with having enough gas etc..
 
Fan control module is brand new and I dis get the air con clutch working by wiring to an independent 12v supply.
I will try and clear the faults.
Thank you for your comments.
 
The turbo pump located under the oil filter runs on after the engine is stopped as the turbo is still hot.

An easy check is to drive so that the car gets fully warmed up, stop and switch off, then get down low at the front to listen for it. It makes a motor whine, audible, but being very small it isn't loud.
 
Using a Carly Obd2 adaptor, i am reading the faults, clearing them however they appear immediately after the next scan.
I have replaced the turbo pump, I couldn't hear it before or now with the new pump... I have checked the fuse, what else controls the Thermostat and the pump? Is it a 12v signal to the thermostat and the pump or does it vary?
Thank you all for your comments and time.
 
Hi everyone. Just an update on what's happened since last conversation.
A specialist has looked at the car and their opinion is that since we have eliminated all other issues, it's possibly the ECU. Thr same alarms are coming up and cannot be cleared.We can send it for testing and hoping it's a burnt component that can be fixed.
A second hand ECU is risky as we don't know if there are any existing issues and it will have to be re virginised to suit my car.
If you hqve any thoughts, please let me know. Thank you.
 
Which 'ECU'? The BSI manages the AC via PSF1 (engine fuse/slave unit) with input from the cabin control panel and other inputs? Swapping the AC control panel would be easy, but not the BSI as it is VIN-coded. It may benefit from a BSI update (dealer), but it is probably not faulty. A fault in PSF1 is more likely than in the BSI.

Have you checked all of the electrical supply and earth points MC35 and MC38 and MC10?

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