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DPF Light on/Emission Control system light on/Glow plug light flashing/No power

matt d Nov 22, 2010

  1. matt d

    matt d New Member

    Driving home from work this evening and the Emission control system light came on, followed by the DPF light, followed by the Glow plug light started flashing and all power was lost!

    I have a 170bhp A3 57 plate. The DPF light has come on before but with some harder driving gone off shortly after.

    Has anyone had similar problems?

    Any idea of the cost of getting this sorted?


  2. c_w

    c_w Well-Known Member

    There's a thread on a Skoda or Seat forum about the processes the engine/ECU goes through with the DPF before getting to this stage. Driving it harder isn't the way to "clean" it it seems, it's constant light load driving (say 60mph cruise), hard driving just fills it up more I think.

    Basically if the ECU detects the DPF is about 45% full it starts a regeneration whilst driving without you noticing, a bit fuller and the light comes on and you must drive the constant 40mph+. I think it's only when it goes beyond 90/95% full that it gets to the stage yours is at and dealers will say it needs a new DPF. Apparently though sometimes the DPF can be forced to regenerate via VAGCOM?

    Cost of a new DPF is £1200 (apparently) or JBS/CustomCode do a DPF delete package which is a replacement downpipe with no DPF and deleting the ECUs DPF regeneration modes BUT it also involves a remap which believe it or not, not everyone wants!

    I wasn't having any DPF issues but I've had my TDI 170 DPF deleted by JBS recently, mainly on the premise/promise of more MPG but I am dissappointed to find that it's not increased it AT ALL, and I can usually extract maximum mpg from most cars (eg 3.2 M3 @33mpg). It's still return high 30s urban and just about scrapes 50mpg at motorway cruises accelerating like the throttle is an eggshell (exactly as before). I was hoping it'd get somewhere near to my TDI 140 which returns high 40s urban and mid 50s motorway without thinking.

    However, in your situation if it turns out it needs a new DPF, I would consider the DPF delete route as it's much cheaper and gets rid of the problem completely. The car becomes much more powerful too, probably less smooth than before though in terms of both power delivery (big torque step at 1900rpm) and slight increase in NVH at low revs (I think the DPF acts as a baffle too as I've noticed the exhaust is slightly noisier on idle and at also in the region of 1600rpm when driving there is a resonance that wasn't there before).
  3. c_w

    c_w Well-Known Member

    Copies from another forum;


    Courtesy of David Bodily Volkswagen Technical Support Specialist

    Diesel Particulate Filter (DPF)

    Detailed below is important information outlining the function and features of the Diesel Particulate filter which all members of your team need to be aware of.

    Diesel particulate filters are becoming more commonplace on diesel engines, particularly sizes 2.0L upwards. This is in order to reduce the exhaust emissions as required by European legislation.

    The prime reason for a DPF is to reduce particulate matter entering the atmosphere. Particulate matter is found in the form of soot, which is produced during diesel combustion. The DPF traps most of the soot which would normally travel down the exhaust and into the atmosphere. The DPF can hold a certain amount of soot, but not a huge quantity and therefore it needs to go through a process called ‘regeneration’ in order to clear the soot loading. When the soot goes through a ‘regeneration’ process it will be converted to a much smaller amount of ash. The ash is non-removable. There are two types of ‘regeneration’, passive and active.

    During long motorway journeys, passive regeneration will occur. This needs no intervention from the engine control unit. Due to the raised exhaust temperatures on a long journey (temperatures between 350 and 500°C), the procedure occurs slowly and continuously across the catalytic-coated (with platinum) DPF. The catalytic-coated DPF is situated close to the Engine, therefore the exhaust gas temperature is high enough (500°C) to ignite the soot particles. Due to this soot is burned-off and is converted into a smaller amount of ash.

    Active ‘regeneration’ is when the ECU intervenes when the soot loading in the DPF is calculated to be 45%. The procedure lasts for about 5 – 10 minutes. Specific measures are taken by the ECU to raise the engine exhaust temperature to above 600°C, these include switching off the exhaust gas recirculation and increasing the fuel injection period to include a small injection after the main injection. The soot particles are oxidised at this temperature.

    The ECU will trigger a regeneration process, if for some reason this is aborted, ie. customer slows down, stops etc, the process will be resumed when regeneration conditions are once again met, above 60km/h (38mph). This will continue for 15 minutes.

    If after 2 attempts of 15 minutes, a successful regeneration has not been possible, the loading will increase. At 50% soot loading, the ECU will continue to maintain maximum exhaust temperatures of 600°C to 650°C to cause a regeneration process. The system will try to run a regeneration process for 15 minutes. If unsuccessful, the system will repeat this process for a further 15 minutes, if still unsuccessful, the DPF light on the driver display panel will then be lit.

    The owners handbook states, the DPF symbol lights up to indicate that the diesel particulate filter has become obstructed with soot due to frequent short trips. When the warning lamp comes on, the driver should drive at a constant speed of at least 60 km/h for about 10 minutes. As a result of the increase in temperature the soot in the filter will be burned off. If the DPF symbol does not go out, the driver should contact an authorised Volkswagen repairer and have the fault rectified.

    At 55% soot loading the DPF light is lit on driver display panel. At this point the customer should follow the advice in the handbook. If they ignore this information and continue driving the vehicle until the soot loading reaches 75% without successful regeneration, additional warning lamps will light up. At this point the customer will also be complaining of lack of power, etc.

    At 75%, regeneration is still possible with the use of the VAS tester. Only when the loading is above 95%, is it necessary to replace the DPF unit.

    Operating Status System Response

    45% DPF Load Level 1
    Normal Regeneration

    50% DPF Load Level 2
    Regeneration at maximum exhaust temperatures

    55% DPF Load DPF lamp
    Regeneration from 60 km/h onwards
    ("See operating manual")

    75% DPF Load DPF, SYS and MI lamp
    Torque limitation, EGR deactivation,

    Regeneration via VAG tester only
    95% DPF Load Replace the DPF Unit

    The Warranty department has confirmed that if there is no fault on the vehicle and DPF regeneration has been unsuccessful due to the customers driving style and the customers failure to comply with the instructions in the handbook, DPF replacement will not be paid for by warranty.

    Common causes for complaint

    • Frequent short journeys – Regeneration conditions are not met.
    Not recommended for sale in the Channel Islands and inner city driving.

    • Customers who continue to drive the vehicle with DPF light on – Continued
    driving with the DPF light on and without successful regeneration results in
    excessive soot loading of the DPF, to a point where it is above 95% loaded.
    At this point regeneration is not an option and replacement of the DPF is

    • Fault 18434 particle filter bank 1 malfunction – Common fault code. This does
    not only relate to the DPF itself, but the entire exhaust gas handling system. This
    can be caused by defective temperature sensors, pressure sensors, additive
    system components (if applicable), poor connections, wiring issues, etc.

    Important Information

    • Before diagnosing a problem vehicle or attempting to perform an emergency
    regeneration, it is important to obtain a full diagnostic log and read out relevant
    measured value blocks. These MVB’s contain important information on the
    condition of the DPF system and are essential in diagnosing the fault. When the
    DPF light is illuminated, it does not necessarily mean that the DPF requires
    regeneration. For further advice, please contact Technical Support with the
    information from the diagnostic log and MVB data.

    • If a problem vehicle arrives with the DPF light, the engine management light and
    the emissions light on. If during your diagnosis and reading of relevant MVB’s,
    you find that the soot loading exceeds 75% (but is still below 95%), an
    emergency regeneration procedure must be performed with the VAS tester.
    Further to this, the customer needs to be educated. They need to understand
    why the lights have appeared on the dash panel. Their attention needs to be
    brought to the owners handbook instructions, so that they are aware of what the
    DPF light means and what to do when it appears. This should prevent
    unnecessary repeat visits for regeneration purposes.

    I have also found that as the car gets older 30K+ miles, you will notice that the regeneration takes place more often.

    ALWAYS, check your oil before any long journey, as DPF regeneration can use a fair bit of oil.

    Some questions and answers that may help;

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

    The DPF regeneration has not been completed during normal driving and now DPF has reached its maximum saturation at which it can still be regenerated. The limit value depends on variant and Model Year, 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. If the glow plug light flashes, the vehicle

    a.) Engine running since start for longer than 2 minutes.
    b.) Calculated saturation higher than 80%.
    c.) Coolant temperature over 70°C for at least 2 minutes.
    d.) No DPF-relevant faults stored in system.
    e.) A defined vehicle speed threshold must have been exceeded (e.g. for >80% loading, 100 km/h)

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

    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.

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