DPF problems

[granjaman]

Help!!! I have refilled my DPF tank with the very expensive fluid from Citroen and a pal of mine has reset the ECU so the DPF warning has gone, however i keep getting the following fault on his Lexia

State of the ECU: DCM34
Reference 1 : 670264
Reference 2 :
Faults present : 1
P2084 : Catalytic converter downstream temperature signal
Characterisation : temperature change coherence
Status : Permanent fault
Location : local .
Variables associated with the fault
Particle filter load state : not charged
Engine speed : 1440 rpm
Particle emission filter flow in volume : 70588 l/h
Inlet pressure : 1.09 bars
air flow sensor air temperature : 18 °C
measured air flow : 365 mg/impulse
distance travelled since the last regeneration : 98 Km
Particle filter differential pressure : 0.01 bars

Is there a sensor i need to check near the DPF/Catalytic convertor?

Any help would be gratefully recieved

Thanks

[Hell Razor5543]

Welcome to the forum.

I am not going to be able to help you with your problem, but I feel certain that somebody will be along soon who can, especially with all the information you have provided.

[granjaman]

Thanks

[RichardW]

What car / engine are we talking about? It sounds as if the temp sensor (which is I believe between the cat and the DPF) is giving some spurious readings. With Lexia it should be possible to see what the temperature is. I suspect the ECU is looking for the temp to be over a certain value for a certain time to complete the re-gen cycle, and it's either seeing it cold all the time, or hot all the time.

[granjaman]

Thanks for that, the car is a 2009 C5 2.0 Hdi Saloon

[masterofinsanity]

had a few dpf problems myself which im working on, im no expert, total novice tbh so take this with a pinch of salt, but i believe your reading should be taken at 3000rpm, pressure seems too low and the cat temp happened on mine when it overheated due to the dpf being blocked.There is a dpf pressure sensor, just check the pipes from the exhaust sensors are all connected, i ended up changing the dpf sensor on mine.