Defreezing mode error in the EEC system
Check that the coolant water level not is to low.Check the ventilation of the urea tank for blockage.To verify that the back flow line heater is working, start the engine and check that the suction line gets warm. If not, check the back flow line for bends, leakage or blockage of the water path. Also check that the water valve opens fully.If the heater is working, check the back flow line and connections for blockage.Check that the vent valve opens fully.For engines with NOx-control software, confirmation of repair requires:- Urea box temperature is greater than -8 degC- Urea tank temperature is greater than -8 degC- Urea temperature in dosing module is greater than -8 degC- Execute the ‘SCR invalidation test’ with SDP3 (takes approximately 30 minutes and needs to be run outdoors)- Or make sure the urea gets defrozen and catalyst temperature is raised to 130 degC If the fault is remedied, the DTC should now be passive.
What you'll see
No driver-visible symptom recorded.
System reaction
The EEC system will not inject any urea, which leads to higher emissions.For engines with NOx-control software, this DTC is classed as a type D failure.
Diagnostic depth
Defreezing of back flow line has failed 12 times, i.e. the urea pressure is still above 0.5 bar after opening the vent valve for 30 seconds.(Refer BOSCH SW-specification Y281S01334-VC0 for more details. Error path: ep04_s_def_ouw.9, hhsm_s_def_ouc.3.)
The defreezing mode error might be caused by: - Blockage in the tank ventilation.- Blockage in the back flow line or its connectors.- Vent valve is not opening fully.