DS5 P0118 and U1218 codes

[Dangerousdave74]

Hi everyone,
Hoping someone can shed some light on my issue. The original thermostat went and have replaced it twice now with the same codes showing up after I have cancelled them.
The first stat lasted 1 week and then the temp gauge went to max and the fans kick in on max. The second lasted 3 days and did the same.
On both of them it reads -40c and won't cancel.
Just before they went, everything was fine with the temp reading normal on the gauge.
Can anyone help?

[Paul-R]

Did you bleed the cooling circuit properly? There are bleed points in several places under the bonnet.

[Dangerousdave74]

I bled the one on the thermostat housing, are there more?

[GiveMeABreak]

U1218 is a generic fault relating to communications and will occur in multiple systems, so it depends on which system this fault code is detected. If you obtained these faults using Diagbox, then you need to run the Global test and let me know under which system or ECU the fault is appearing.

As for the P0118 fault, did you buy a decent branded sensor (hopefully nothing from ECP), as cheap sensors can often be dead on arrival.

Fault Code:	P0118
Description of Fault:	Engine coolant temperature sensor: Short circuit to positive or open circuit: Value too low. Voltage higher than 4,78 V for more than 1 s.
Conditions for Fault to clear:	Driving with the engine hot for 5 minutes.
Downgrade Modes whilst Fault is active:	Request for stopping of the aircon Lighting of the coolant temperature warning lamp Deactivation of the EGR function Cutting of the exhaust heat saver function Deactivation of the exhaust heat saver pump Activation of the cooling fan at fast speed Deactivation of the injector resetting strategy Request for opening the piloted flaps (Controlled air inlet module) Deactivation of the after-sales test for detection of leaks on the diesel fuel high pressure circuit
Symptoms:	Diesel fuel consumption a bit higher Engine overheating with illumination of the engine coolant temperature indicator light Engine hesitating, cutting out Lack of power Noise
Suspect Areas:	Electrical harness Connectors Coolant temperature sensor

So this would indicate a fault electrically or with the sensor itself. However the U1218 code needs to be resolved as if there is a comms issue on the network this may also have an impact - we won't know until you can provide further info on the system it is related to and your VIN so I can ensure it is tied to the correct EMS.

[Dangerousdave74]

Vin is VF7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

Ok, so I assumed the correct engine for your vehicle so the above fault code is relevant. If you can provide further context for the U1218 fault I can help with that code a little more.

[Dangerousdave74]

All it says on the report is.
Inter systems CAN-one of the parameters present in a data stream sent by the BSI is invalid.

[Dangerousdave74]

The P0118 code says-
engine coolant temperature sensor circuit open or short to positive.

[GiveMeABreak]

Yes, I know that, as I've already provided you with that fault descriptor in a previous post above, maybe you missed it?

viewtopic.php?p=742407#p742407

It's the U1218 fault I need more context on.

[Dangerousdave74]

Sorry, what context do you need?

[GiveMeABreak]

U1218 is a generic fault relating to communications and will occur in multiple systems, so it depends on which system this fault code is detected. If you obtained these faults using Diagbox, then you need to run the Global test and let me know under which system or ECU the fault is appearing.

....However the U1218 code needs to be resolved as if there is a comms issue on the network this may also have an impact - we won't know until you can provide further info on the system it is related to and your VIN so I can ensure it is tied to the correct EMS.

[Dangerousdave74]

This is all the info I have, I don't have diagbox.

[GiveMeABreak]

Ok, so that's no good to me unfortunately as I can't help you with aftermarket diagnostic tools. If you had used the proprietary diagnostic software like Diagbox, it would provide the context of the fault code, in other words, when conducting a diagnostic scan, the fault code would be shown against the specific ECU that is reporting the fault.

As it stands and as I've said in my previous posts, U1218 is a fault on the data network, but we can't tell which system ECU is reporting it as CAN networks link many ECUs together in the vehicle. So until you resolve this fault, you need to be careful about fixing other faults - as they may a symptom of the U1218 data network / comms fault.

[Dangerousdave74]

Ok, thank you very much for your help.
Once I get it sorted, I will post the findings on here that will hopefully point other people in the right direction.
Thanks again.

[Paul-R]

I'm afraid I don't know exactly where the bleed points are but have a look near to where the heater hoses go through the bulkhead. There may be more elsewhere - just look for things that look a bit like tyre valves.