Golf V Intake Manifold Flap - Airflow Control & P138 Error

Hello community,

I have a Volkswagen Golf V GT Sport 2.0 TDI 170, manufactured in 2007, with engine code BMN.

This morning, I was driving and suddenly the yellow warning light started flashing, and the display showed "Engine fault - visit a workshop."

When I turn the ignition off and on again, the error disappears, but after a few hundred meters, it starts blinking again.

I once scanned the vehicle with VCDS, and it showed the following (see the images attached).

"Intake manifold flap for airflow control, P138."

I then cleared the error code, drove the vehicle once around the block, and then it started blinking again, and the error memory now shows:

"Is the air mass flow rate too low in regeneration mode?"

The car still drives and has power, but what could be the problem?

Update: I drove yesterday and today, and now none of the lights are flashing anymore.


Perhaps someone has some advice?

What I still wanted to know, because many people define it differently.

Is the intake manifold flap the part that sits in front of the EGR valve, essentially like a throttle valve, or is the intake manifold flap the swirl flaps?

I always get confused about that.


I would really appreciate your help.

Best regards,

Hello, has the problem been resolved yet?
I'm currently experiencing the same error.
Volkswagen Golf 5, 2.0 TDI engine code BMN.

Best regards,

It's not a rare mistake . You can buy a new throttle body, which is also available from independent retailers.

Yes, the error has been fixed.

I removed the throttle valve and it was stuck, making it very difficult to open and close due to heavy carbon buildup.

I cleaned it, and then it started working again. However, I decided to buy a new one, and since then, everything has been quiet.