BMW X3 F25 20d engine check light on

Detailed explanation is available on YouTube!

BMW F25 X3 X-DRIVE 20d

Engine check light and carbon cleaning

We are visiting from Toyama Prefecture.

This is the case of a vehicle that has traveled 127,000km.

I'll diagnose it right away.

A list of fault memories!

It looks quite crowded, but to sum it up:

- EGR valve is not working properly

・Decrease in air flow rate of EGR cooler (clogged)

It means that.

Let's break it down.

Check the removed parts

EGR junction

Inside the intake manifold

Around the intake port

A considerable amount of soot has accumulated.

What about the problem areas?

This is the EGR valve.

There is a phenomenon where soot gets stuck in moving parts.

This can be improved to some extent by cleaning, but the springs may deteriorate over time.

Considering the decrease in spring force, I will replace it with a new one this time.

One more point, the condition of the EGR cooler

I'll take a look here.

Soot is accumulating on the cooling fins.

This obstructs the air flow and causes the check light to come on.

Scrape out the accumulated carbon!

Next, go to the ultrasonic cleaner

DPF cleaning is also performed while cleaning parts.

The effectiveness will be maximized when combined with intake and EGR cleaning.

Condition inside the DPF before cleaning

Condition after cleaning. Perfectly clean.

Perform DPF combustion run after assembly

Intake port also cleaned

*We have newly introduced a walnut blaster that uses walnut shells.

In addition to the conventional manual cleaning, it is now possible to perform cleaning with even higher precision.

(The image is an example)

In the meantime, I finished cleaning the parts. It's finished!

After washing. Like new.

Also the EGR cooler that had the problem

This improvement is possible without replacing parts.

Replace the EGR valve with a new one.

After assembly, put it into DPF regeneration mode and do a test run.

BMW has a system that does not allow forced regeneration of the DPF unless the vehicle is running.

This is the data after the work is completed.

The position of the EGR valve will follow the specified value.

By replacing it, the poor movement caused by catching was resolved.

DPF soot accumulation amount and exhaust gas back pressure (exhaust resistance = degree of clogging)

has also been greatly improved.

Cleaning the intake/EGR and DPF before and after will have the greatest effect!

BMW diesel engine.

Unlike gasoline engines, engines such as VANOS and Valvetronic

There are no mechanisms involved, and the structure is extremely simple.

That much





The balance of these accessories is very important.

If any one of them goes out of order, the overall condition will deteriorate rapidly.


・To give an example

Soot accumulates in the intake and EGR over time

Combustion status deteriorates due to deviation in sensor values

Increased amount of soot generated during combustion

DPF tends to become clogged

Accelerated soot accumulation in intake/EGR


An example is


Of course, this will also have a negative effect on the injector.

We are also considering introducing injector cleaning equipment in the future.

Regarding soot generation and the vicious cycle of EGR and DPF

We will introduce you in detail in the blog and video below.

BMW 320D F31 intake/EGR "soot" carbon cleaning – car life studio ConSense

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