cooling fan problem p0115

[pugmiester406]

hi guys n gals. I have a 406 2.0 hdi estate on a 53 plate. pretty sure its the d9 running the full multiplex system...... ok... here goes!!
pulled up a couple of days ago and the cooling fan is running at wot sounds like half speed whenever you turn the ignition on. regardless of temp its running then it will cut off a few seconds after you turn off ignition. the air con is running fine but I don't think on these full multiplex models the cooling fan cuts in with the air con anyhow.... the temp sender has been replaced as has a lot of my hair all fuses are ok so im stuck really.. getting the code p0115 from fault code reader... could anyone please help as its really p*ssing me off!!! thanks.. lee

[grasmere59]

The cooling fan on a fully mux D9 has to double up as the water coolant and the air con condenser fan.

[Doggy]

I think pugmeister's right, the cooling fan should only run as necessary to maintain water temperature, (more or less never in this country), or to reduce condenser pressure, (mine almost never needs to run to do this either). Mind you, if the aircon's off you should definitely be able to discount that as the cause.

P0115 = Engine Coolant Temperature Circuit Malfunction

Could mean unstable temperature, (airlock maybe - it can be a pig to get all the air out).

You would get to the bottom of it much quicker with PP2000 - you could monitor coolant temperature, condenser pressure, evaporator temperture, etc. Via actuator test, you can run the fan at all speeds and check all the clocks work.

[pugmiester406]

thank you for ur replys, I just wanted to give u some more info on wot, and therefore wot I haven't done... I tested the voltage across the temp sender plug (green on the side of the thermostat housing) this came out reading 5 volts? could anyone confirm this as if it should be 12v there ly the problem. also. in the Haynes im reading the diagram for the dw10 engine. is this the correct one?. it shows no rad fan switch which is correct I believe but it does show a relay called a pressostat... I would like to know where this is? it also shows a twin speed resistor. I did look for this resistor in the plastic shroud next to the cooling fan but as per usual Peugeot have moved them. I also believe? again im not 100% sure that this system is set up to be fail safe.. in other words if u was to unplug the temp sender the ecu will switch the fan on..
could anyone confirm on pulling out this plug wot speed their fan runs at? if its flat out I can discount that part of the circuit... to recap....
1 temp sender plug voltage
2 pressostat relay location
3 twin speed resistor location
4 dw10 Haynes wiring diagram correct?
5 temp sender plug disconnect the fan speed?
many many thanks to all that try and help me and to those who already have on this great site.....

[pugmiester406]

apologies......... the pressostat named in the Haynes may well be a switch and not a relay

[grasmere59]

The fan has a built in fan speed controller on the back of the motor,there is a grey control relay I think on the front lower N/S inner wing (looking at the car) somewhere.My fan run cycles on and off at half speed whenever the A/C is on.

[Doggy]

Presostats on early, (semi-mux) cars are pressure switches with one pair of contacts used to run the fan at low speed, AFAIK. This is what's shown in Haynes.
On later cars, the presostat is replaced by an identical looking analogue pressure sensor, that connects to the engine ecu. The engine ecu manages aircon operation and fan speed, as grasmere describes above.