[Warning Light] Dpf risk of blocking

[cycle silly]

Strange one this. A 2013 1.6 hdi 104k,it has flashed up the light and gone into limp mode once the van put under load joining motorway.  The Eloys tank is around 60% full and the pump is overfeeding the solution. Garage has reset limp mode checked filter and recalibrated? pump. All was ok until put under load again same error and limp mode. Garage has never seen this before so unsure of the possible causes.
Cheers 
Dave

[Oi69]

If they got lexi force a regen and see what happens or its £180 round corner from us to have them cleaned out

[cycle silly]

They have done a regen, but problem reoccured.

[Sol]

Could be an issue with the differential pressure sensors for the DPF. A large enough difference at both ends will signal the ECU that the DPF is blocking up even if it's not. One of them could be faulty.

The only way to really tell is to pull the DPF and look inside, and use the Citroen software (DiagBox) to read the pressure sensor values to see if they still send the wrong value if it isn't blocked.

The ECU is giving the warning based on the data it has access to.