DPF Smoke: Passat 3C Engine Revving Issues

Translated on 31-07-2026, 21:40.

Hi.
I have two problem vehicles. One is an A4 ADR model. Apparently, the A4 revs up to the limiter. I've been driving the A4 for 100km and haven't been able to reproduce the issue yet. According to the report, it always happens when releasing the accelerator, so I initially thought it might be a stuck throttle body or a problem with the gas cable. However, I found nothing. Today, I cleaned the throttle body and adjusted its basic setting. So far, everything seems okay. What I've noticed is that the load indicator only goes up to 85.9%. I'm not reaching 100%. Could it be a faulty throttle position sensor? Can this be readjusted, or do I need a new throttle body? What else could explain or cause the high revving?

Okay, let's talk about the Passat. My brother-in-law has a 3C model with a 170 hp engine and a DPF (Diesel Particulate Filter). The Passat occasionally produces very strong blue smoke with a pungent odor. I believe this is caused by the DPF.
"I haven't had the car yet, so I don't have any measurements. The dealer said that the smoking is normal. What I don't think is normal is the white/blue haze that appears behind the car while driving. How can I check the filter system, or are there any known issues that could be causing problems with the DPF?"

Best regards, Bolzer.

Translated on 31-07-2026, 21:42.

There was also a report of a smoking BMR (battery management system) in the 3C on Spritmonitor.de.
He then exchanged it.

Mine doesn't do that...

Translated on 31-07-2026, 21:43.

Hi.
Thanks for the tip. I sent him an email. Let's see what happens.
Best regards, Bolzer.

Guest Free account, no CAN development support

Please be friendly and install the new update.

Translated on 31-07-2026, 21:43.

Hello Lars,
We've already installed the update. However, this issue only started appearing long after the update was installed.
Best regards, Bolzer.

Translated on 31-07-2026, 21:44.

Hi.
Okay, so the A4 is fixed. The problem was that several hoses located under the intake manifold were damaged/porous and cracked. Also, the plastic parts of the crankcase ventilation system were broken. However, the actual underlying issue didn't manifest itself in my case.

The Passat:
"@Dieselmartin. Even with the part that was replaced, the workshop said that this is normal."
Let's see how things develop. I'll keep you updated.
Best regards, Bolzer.