Field Remedy: 2341

Remedy:

Important: In case of complaint, please follow TSB/Field Remedy
           database, in particular TSB 1976, 2043, 2054, 2260.

Question 1: Has the ECU supplied black box data to give information on 
            the last regeneration or regeneration sequence?

Answer: All applications show the current loading status in percent, 
and the distance covered since the last regeneration or regeneration
attempt. TECH 2 gives no information on whether the previous 
regeneration (or regenerations) were complete and successful.

Question 2: The glow plug symbol is flashing. Why? What should be 
            done?

Answer: The DPF regeneration has not been completed during normal
driving and has now reached its maximum saturation at which it can 
still be regenerated. The limit value depends on variant and MY, 
but is in the range of 105% - 125%.
Possible causes for this are:

a.) Frequent short distance journeys, i.e. high soot loading while at 
    the same time regeneration of the DPF does not take place because 
    the conditions necessary were not fulfilled.

b.) Frequent interrupted regenerations, i.e. the engine was switched
    off during regeneration. Applies to short journey drivers who 
    have at least fulfilled the conditions for triggering 
    regeneration.

Note:    Regeneration is carried out more often (2 - 3 times) during 
           the first 1000 km of driving in order to achieve a defined 
           loading status of the DPF. This is necessary to reduce 
           component and system tolerances, and forms the basis for 
           precise calculation of the soot loading in the DPF.

Important : For both causes if the DPF Lamp is active, engine should 
be kept on, e.g. the vehicle should be driven until it goes off. 
If DPF regeneration is successfully completed the DPF lamp goes off!

General advice : 
Do not perform any service regeneration in case of only having DPF 
lamp/code 55 activated 

Question 3: What conditions are required for the DPF to begin 
            regeneration?

Answer: The following conditions must be fulfilled for regeneration to 
begin. 

a.) Engine running since start >
 2 minutes.
b.) Calculated saturation >
 80%.
c.) Coolant temperature >
 70°C for at least 2 minutes. 
d.) No DPF-relevant faults stored in system.
e.) A defined vehicle speed threshold must be exceeded in some cases
    (e.g. for 80%-100% loading, one time 100 km/h), at loadings above 
    100% the speed does not matter.

Question 4: After service regeneration, TECH2 data list shows 
            a current loading status of 70% or 78%. Why?

Answer: The regeneration intensity of the static regeneration is not 
as effective as that of dynamic regeneration. The value is therefore 
set to 70% - 78% loading so that the ECU then triggers a dynamic 
regeneration when the required conditions (see question 3) are 
fulfilled.

Exception: Vehicles equipped with 1,7 liter Diesel engine will show 
a saturation level of 32% after service regeneration.

Question 5: Under what conditions is regeneration interrupted/ended 
            once it has started?

Answer: Normally when regeneration has been successfully completed, 
or:
a.) After a maximum regeneration time (20 - 25 min.).
b.) If the engine is switched off or has stalled.
c.) If the engine is left idling for a long time (5 - 10 min.).
d.) If 1000°C is detected by the exhaust temperature sensor.
e.) If during regeneration, a fault is detected on the components 
    relevant for combustion (injection/intake system).

If a regeneration is interrupted once started but before it has been 
50% completed, the glow plug lamp flashes on the next engine start 
(cold or hot) and regeneration begins again once the operating 
conditions (see 3) have been fulfilled.

Question 6: The DPF loading is (far) below the threshold value for 
            the flashing glow plug lamp, but the customer comes in 
            with the SVS light on and the DPF clogged. Why?

Answer: In this case, there is very likely a hardware fault or tuning.
This fault is usually due to a leak in the air-carrying parts. Often 
there is a split in one of the charge air hoses or charge air cooler. 
Due to the leak, which the ECU or loading model does not detect, the 
engine will emit more smoke if the pressure difference remains below 
a defined threshold. The increased smoke emission can clog the DPF.
Furthermore, a disproportionately high loading of the DPF can be due 
to a (partly) open EGR valve.

A tuned engine emits more smoke than calculated in the soot loading 
model. This may result in a clogged DPF without any customer 
notification.
In general please check the field remedy database for known fault 
pictures and diagnosis instructions.

Question 7: How long does complete regeneration take?
            a.) In the most favourable case?
            b.) In the least favourable case?

Answer: 
a.) Under constant conditions, i.e. the exhaust temperature 
    necessary for regeneration always lies above the required value, 
    for example during motorway/cross-country driving, the average 
    regeneration time is 10 minutes.

b.) Vehicle conditions such as long down-hill descents, frequent 
    driving in the low-load range (city driving, idling) allow the 
    exhaust temperature to fall. If the conditions for triggering 
    regeneration were fulfilled, the active regeneration time can be 
    extended up to 25 minutes (depending on engine type). If complete 
    regeneration is not possible within this period, the regeneration 
    will be interrupted.

Question 8: How does regeneration affect the oil life?

Answer: On each regeneration or attempted regeneration, a certain 
diesel fuel amount is injected into the engine oil which reduces the 
oil life. If the "INSP" light in the instrument cluster comes on, the 
engine oil is exhausted and must be changed. Failure to do so could 
damage the engine.

Question 9: Is the DPF sensor important for the regeneration 
            procedure?

Answer: The sensor does not initiate the regeneration, which is based 
on a model. The DPF sensor fulfils purely a diagnostic function to 
monitor the counter-pressure in the DPF.
Exceptions are the Antara, Captiva, Z20DTx; on these models, the DPF 
sensor is involved in triggering the regeneration.

Question 10: How does the Soot loading value in ECU behave?

a.) After SPS programming.
b.) After a change of ECU.
c.) After disconnecting the battery.

a.) After a pure SPS, the loading status is retained. On a change of 
ECU or reprogramming of the existing ECU, after reset the loading 
status jumps to 104% (e.g. on the Z19DTx), and then regeneration takes 
place. Variations are possible depending on model year or application. 

b.) The current soot loading value will be stored on Tech 2 flashcard 
prior ECU removal. This value will be programmed into new Service ECU 
via ECU reprogramming.

c.) No effect.