C4 Picasso 2015 (B78 plate) Heating problems

[GiveMeABreak]

It is not an easy job and that is why they are charging this amount as half the dash may have to come off to get to the unit. A DIY repair often involves cutting out parts of the plastic housing to get to the spindles and then gluing everything back up afterwards! .

I would be 100% certain that this is the problem before going down this road. Perhaps if you posted up the symptoms we can offer some other advice or checks.

[mnsdall]

It is not an easy job and that is why they are charging this amount as half the dash may have to come off to get to the unit. A DIY repair often involves cutting out parts of the plastic housing to get to the spindles and then gluing everything back up afterwards! .

I would be 100% certain that this is the problem before going down this road. Perhaps if you posted up the symptoms we can offer some other advice or checks.

Ok many thanks for your reply Marc.
The problem is the same as other said above, no heat on driver side.
They started with changing the Heating ECU ” apparently because of Service bulletin from Citroen.”
The fault Was not cured.
Then changed the heating box, still same
Now they said the heating matrix also need to be changed.
When I have questioned them “thanks to the knowledge I got from FF” that the only part was faulty was the heating matrix.

And I don’t want to pay for other parts, they are coming up with the excuses that the driver side heating box spindles wasn’t working properly.

[GiveMeABreak]

Ok as I see it, there is a catch 22 situation. It is rare for the actual stepper motors to fail these days, so adjusting the temperature distribution flaps may not help at this stage because the motors will still be heard to operate, whether they are turning the spindle or just turning inside a worn spindle socket.

Without any heat supply on the driver side, you won't be able to test whether the actual temperature distribution is working and so rule out the flap mechanisms.

So a more common scenario would be a blockage in the heater matrix. It may be worth your while seeing whether this can be cleaned through and flushed first to see if that clears any blockage. If not, then that may be where your problem is - where the hot coolant is only getting half way round the system. This can happen when the coolant system hasn't been checked and serviced, or where the wrong coolant or so called 'leak fillers' have been added which may have gunked up the system.

Either way it is going to take some investigation to identify, but I would start on the heater matrix to begin with as that is typically the culprit for the issue you describe. Changing the heater matrix only requires some of the lower interior fascia panels removing for access and the air filter housing in the engine bay, so does not require the dash dismantling. So I would get some advice around that.

[mnsdall]

Ok as I see it, there is a catch 22 situation. It is rare for the actual stepper motors to fail these days, so adjusting the temperature distribution flaps may not help at this stage because the motors will still be heard to operate, whether they are turning the spindle or just turning inside a worn spindle socket.

Without any heat supply on the driver side, you won't be able to test whether the actual temperature distribution is working and so rule out the flap mechanisms.

So a more common scenario would be a blockage in the heater matrix. It may be worth your while seeing whether this can be cleaned through and flushed first to see if that clears any blockage. If not, then that may be where your problem is - where the hot coolant is only getting half way round the system. This can happen when the coolant system hasn't been checked and serviced, or where the wrong coolant or so called 'leak fillers' have been added which may have gunked up the system.

Either way it is going to take some investigation to identify, but I would start on the heater matrix to begin with as that is typically the culprit for the issue you describe. Changing the heater matrix only requires some of the lower interior fascia panels removing for access and the air filter housing in the engine bay, so does not require the dash dismantling. So I would get some advice around that.

Many thanks Marc for detailed reply.

Oh I see, thats mean the garage had started changing parts from the wrong end. Can’t believe, they left me without car for months (parts delivery delays and two week to fit,) and they are even Citroen main garage.

One more point if the driver side spindle was not working there should be no cold(ac) nor hot air?
As in my case the problem started in winter, in summer 2020 the ac was working fine.(actually it was very good)

And lastly What will be the best way to challenge them as I need the car back as soon as possible.

[GiveMeABreak]

Obviously it's difficult for me to properly help from here, but if you have it at the dealer, then I would expect them to be able to find the issue - but as I said previously, it may be difficult to accurately diagnose the issue 100% because you are dealing with cool and hot air circuits and the distribution / mixing side of these 2 elements.

This is the 'Thermal Loop' of the system with Automatic Air Conditioning system:

"D" Cold Air Circuit.
"E" Warm Air Circuit.
(9) Heater Matrix.
(10) Passenger Compartment Air Heating Resistor (*).
(11) Air Conditioning Evaporator.
(13) Cooling Condensor.
(14) Air Conditioning Compressor.
(15) Internal Combustion Engine.
(16) Cooling Pressure Relief valve.

[mnsdall]

Many thanks Marc you are very kind and helpful. I Will chip in some donation.

[Mexico14]

It is not an easy job and that is why they are charging this amount as half the dash may have to come off to get to the unit. A DIY repair often involves cutting out parts of the plastic housing to get to the spindles and then gluing everything back up afterwards! .

I would be 100% certain that this is the problem before going down this road. Perhaps if you posted up the symptoms we can offer some other advice or checks.

Ok many thanks for your reply Marc.
The problem is the same as other said above, no heat on driver side.
They started with changing the Heating ECU ” apparently because of Service bulletin from Citroen.”
The fault Was not cured.
Then changed the heating box, still same
Now they said the heating matrix also need to be changed.
When I have questioned them “thanks to the knowledge I got from FF” that the only part was faulty was the heating matrix.

And I don’t want to pay for other parts, they are coming up with the excuses that the driver side heating box spindles wasn’t working properly.

I had this problem. Changing the matrix sorted it. However I not have a new problem.. When changing the temperature it doesn't seem to alter the air flow temperature until I set it to "high" or "low" I'll hear a flap closing sound then the drivers side for example will blow cold air and the passengers will be blowing hot until I turn the fan off then back on they return to the same temperature.

Does anyone know what will remedy that? The dealers mentions they'd had a bulletin on the ecu..

I don't really trust my dealers much. I complained of a knocking sound from the front, they said it was the droplinks, replaced them, it was still there! Then they replaced the struts... Still there! Then the strut mounts... Still there. Took it for an Mot and they confirm the problem was the track rod end ball joint and were surprised it wasn't noticed as its hanging on!

[Frenchiemech28]

This is an extremely common fault on this vehicle .

Citroen Peugeot dealer master technician here.

Heater core blocks up commonly around 120-150km or 80k miles.

Need to make sure u always use the blue coolant or U will have issues with blockages of the heater matrix. It can be fixed cheaply by disconnecting heater pipes on fire wall and back flushing the the core / matrix after filling the core with a radiator flush additive and letting it soak. Otherwise replacement if the core / matrix. Luckily dash out is not needed. It's a simple replacement procedure anyone could do with basic knowledge.

[Palo1973]

Good Morning

I have about the same problem too with my heating. Hot air is coming from left side panel, and the left side of the middle panel. The right side of the middle panel and on the right side there's cold air.
What the mechanic found is the heat radiator (or matrix ? ) needs to be replace.
Can you please send me the part number of it, and the repair booklet for the car ?
The VIN number is : VF7**************[VIN obfuscated, can be read by forum staff]

Thanks
Cristian

[Mexico14]

Upto now had the heater matrix changed and recently the ecu - that did nothing. Citroen reckon it's now a condenser box and will cost on the region of 940 and aren't sure if the extended warranty will cover this? The warranty company are sending out their guy to have a look at the car.

Am I likely to be left to deal with this problem out of my own pocket? I can't see it anywhere in the exclusions on my warranty paperwork.

[GiveMeABreak]

As far as I'm concerned it should be a warranty covered item as this is not realistically deemed a 'wear & tear' item like a clutch or brake discs / pads etc. The evaporator box is not a user serviceable item not a service item and therefore should be covered! stand your ground and do not be afraid to take it further. I've done this several times and won in each case without question.

The heating system is an essential part of the vehicle's safety systems - clear visibility and if it's not working is a hazard.

[chiengi]

Hi! Slaay, have you sorted it out of Heating problems. I have the same problem with my Citroen C4 picasso 2014.

[BoSee]

Excuse me for jumping in on this heater problem thread 2 years late, but the parts diagram posted by Givemeabreak, is the only reference I can find for the part I need replacing on my car, which is a 2011 LHD edition. See: the part numbered 14 on the diagram, the 2 identical dual-levered long arms are both perished and need replacing. Is there a part number for item 14?

[Frenchiemech28]

This is a known issue on all 2014 onwards Picasso or 308 vehicles and there is a tech bulletin on the issue as well. Denso heater system and the cores clog often. The replacement core is cheap and it can be easily changed without dash out. Just loosen the bolt securing the heater pipes on firewall to allow the pipes to move freely and disconnect from heater core end.

Slide out the old core and replace. Genuine kit includes new clamps and O rings.

You can also fix by using a flushing tool with compressed air and water but due to access it's just as easy to replace the core.



Tim

Citroen Peugeot specialist mechanic

[Frenchiemech28]

This is a known issue on all 2014 onwards Picasso or 308 vehicles and there is a tech bulletin on the issue as well. Denso heater system and the cores clog often. The replacement core is cheap and it can be easily changed without dash out. Just loosen the bolt securing the heater pipes on firewall to allow the pipes to move freely and disconnect from heater core end.

Slide out the old core and replace. Genuine kit includes new clamps and O rings.

U can also fix by using a flushing tool with compressed air and water but due to access it's just as easy to replace the core.



Tim

Citroen Peugeot specialist mechanic