Why did the car’s DPF or FAP light come on? (2022)

11 Min Read
Car's DPF or FAP light

For a significant time, diesel fuel enjoyed a reputation for being exceptionally eco-friendly. Drivers felt reassured by the low fuel consumption and the possibility of using powers that were grown organically.

Compression ignition, on the other hand, is a potentially hazardous source of toxic substances. Particularly problematic is the soot that is inevitably produced whenever diesel fuel is burned.

Car's DPF or FAP light

Soot is a form of fuel that has not been completely consumed. In older diesel vehicles, only combusted diesel is released directly into the atmosphere without any cleaning process.

When breathed in, it acts as a cancer-causing agent that is on par with the risks posed by the nicotine and tar found in cigarettes.

Because of this, carmakers were mandated to install emission control systems in all newly manufactured diesel vehicles under the law. A method for the purification of exhaust gases that is both highly effective and efficient.

Having only a temporary effect

In diesel vehicles, the diesel particulate filter serves only partially as an actual material converter, in contrast to the catalytic converter found in gasoline vehicles.

The function of the particulate filter, as suggested by its name, is to remove soot particles from the exhaust gas flow.

No matter how large a filter is, it will be saturated to the point where it will no longer be able to function as effectively as it once did. The PDF is capable of cleaning itself.

When the exhaust gas temperature is raised to an artificially high level, the soot will burn to ash. This results in a lesser amount of volume being left in the filter.

Despite this, the ash itself is still present in the PDF. At some point, the diesel filter will also be unable to handle more debris.

When this happens, the self-cleaning program has exhausted all of its options, and the engine control unit warns of an error.

On the dashboard, there is a control lamp that illuminates to indicate this. This caution should not be disregarded in any way.

If the filter becomes clogged, there is a possibility that the engine will completely break down.

However, before that point, the engine power will significantly decrease, while the fuel consumption will increase substantially.

Repairs mandated by the law

To pass a general inspection, it is necessary to have a diesel particulate filter that is operating correctly.

At the time of the check, if the inspection body finds that the filter has built up debris, you will not be given the new label.

Nevertheless, this might end up being quite pricey, depending on the kind of car you drive. One should spend at least 1,100 dollars to purchase an entirely new filter and replace the old one.

However, the price may end up being significantly higher. However, there are other opportunities available.

Altering instead of replacing with something new

The DPF can be cleaned again using recognized and approved techniques, nearly restoring it to a new state. There are two approaches to this issue:

  • Burn
  • Rinse

After being disassembled, the diesel particulate filter is put in an oven and burned to make fuel. There, it is heated to such a high temperature that any remaining soot is reduced to ash as the process continues.

In the final step, compressed air is used to blow away any trace of the ash that may still be present. The filter is cleaned by passing an aqueous detergent solution while it is blown through.

Additionally, the filter is subjected to pressure from both sides during this process. This is the only method that will clean the ash from the DPF.

The ash accumulates in closed bearings on one side, which is the reason for this behavior. If only one side of the filter is exposed to the compressed air, the ash will remain in its original position. As a result, there is no natural cleaning accomplished.

Often, recognizable brand names are not any more beneficial than generic alternatives

Do-it-yourself products for cleaning diesel particle filters are problematic as a result of this situation. These days, a broad variety of wonder goods available on the market promise an efficient and thorough cleaning of the particulate filter. Unfortunately, reputable, well-known companies are also participating in these competitions for the quality of the lubricants they produce.

They are all touted as containing material that, when injected into the threaded hole of the lambda probe and then released under pressure, can clean a blocked filter.

On the other hand, as we have stated previously: To ensure that the filter is thoroughly cleaned, it is necessary to treat it from both sides. When the filter is mounted, there is only one way to approach the problem of treating it. Consequently, these methods of filter cleaning that are appropriate for domestic use are not particularly effective.

Why did the car's DPF or FAP light come on

The issue is of much greater concern

In addition to the problem’s limited impact from the existing techniques, the injection process also presents a further, much more serious challenge: the cleaning agent’s potential to create a hard plaque that resembles concrete when coupled with soot and ashes.

Even the most intensive cleaning procedures, such as burning at temperatures higher than one thousand degrees Celsius, are pointless in this scenario.

A filter that has been damaged to such an extent can only be repaired using a brand-new component, which is unfortunate. A professional cleaning service is available for as little as 199 dollars, and it has been verified that it is effective. This is only one-fifth of the original cost of a diesel particulate filter that is more affordable.

To save money and prevent travel expenditures, disassembling at home

Thanks to its straightforward design, the DPF can be taken apart without too much trouble. You will save a significant amount of money if you take apart the particulate filter you use at home and send it to a service provider.

The pitot tube or the lambda pressure probe breaking is the worst-case scenario. In this scenario, service providers offer an additional service consisting of drilling and repairing the threaded hole as an option for customers. This is rarely more expensive than purchasing a new DPF.

When the filter is taken apart, the rest of the exhaust system can be carefully examined without having to take the vehicle apart again.

When it comes to the cost, the filter unit is by far the most expensive part of an exhaust system. If the vehicle needs to be lifted anyway, this presents an excellent opportunity to replace any components of the exhaust system that are damaged or worn.

It is a philosophical question of whether a lambda sensor should be reused. It is not necessary to install a brand-new lambda sensor or Pitot tube in a DPF that has been remanufactured.

However, if the component is repaired or replaced while the filter is being overhauled, no error will be made. The entire assembly will attain a new and well-defined state by proceeding in this manner.

Always investigate the underlying reason for something

The average life expectancy of a diesel particulate filter is 9,500 miles. The prerequisite is that it be driven in at least one different direction.

Longer trips on the highway lasting more than an hour should be considered part of the routine operation of a vehicle. The engine and exhaust gas temperatures necessary to burn the residues stored in the DPF will never be reached if the diesel vehicle is only driven for short distances.

If the particulate filter clogs up substantially sooner than usual, the engine could experience a serious malfunction. In this scenario, engine oil makes its way into the combustion chamber and, consequently, the particulate filter. It’s possible that:

  • Turbocharger with a manufacturing defect
  • An improperly functioning cylinder head gasket
  • Inadequate sealing of the valve stem
  • Defective compression segments

Some processes can be followed in order to precisely examine each and every one of these defects.

As a result, the engine should go through a comprehensive inspection for this kind of damage before making use of the new or reconditioned DPF.

In that case, the new component will quickly become clogged, and the damage to the engine may progress more rapidly than usual. Then the entire process of replacing the filter unit was a waste of time and money.

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