2009 Jetta TDI DPF regeneration question

[Steve Sexton]

I just had the Diesel Particulate Filter replaced along with the EGR. Shop notified me that the fan control module needs to be replaced. They stated that the vehicle will not enter regeneration until the FCM is replaced. When I asked them if that applies to passive regeneration as well as active, they "could not say for certain."
I am having a hard time finding a FCM, and am afraid to drive the car if the DPF will not regenerate under passive regeneration conditions, due to the bad FCM.
Any advice?

 

[TurboABA]

What codes are you seeing?
Passive regen happens while you drive, so none of the "failed" components will stop it from happening..... passive regen happens very little as you need the correct load\conditions to heat up the system sufficiently.

 

[oilhammer]

The fan controller is integral with the left fan, and the ECU runs the fans at full speed during a regen, hence the reason why it may inhibit a proper regen event if the fans are not working correctly although I cannot say I have ever seen that happen. Regardless, you need to fix the fan(s).

 

[TurboABA]

Something sounds fishy here..... why was your DPF replaced, and how did you know it needed to be replaced?
Did you get the old parts back? Do you have VCDS or an actual scan of the issues before your stuff got "replaced".

 

[TurboABA]

The fan controller is integral with the left fan, and the ECU runs the fans at full speed during a regen, hence the reason why it may inhibit a proper regen event if the fans are not working correctly although I cannot say I have ever seen that happen. Regardless, you need to fix the fan(s).

For active regen yes, but the op asked about passive.
By definition, passive happens without ECM assistance\help.
I'm seeing all kinds of red flags with this shop's claims.

Passive regeneration
With passive regeneration, the carbon soot particles are burnt off continually without intervention from the engine
management system. The particulate filter is positioned in close proximity to the engine. This assures that exhaust
gas temperatures of 350-500 °C are reached on motorways, for example. The carbon soot particles are thereby
converted into carbon dioxide by a reaction with nitrogen oxide. This gradual process occurs slowly and continually
through the platinum coating, which works as a catalyst.

 

[TurboABA]

And if I think back, the '09 had the "one pc" DPF + NOx system (unless it had already been replaced once) so that's why I'm asking these stupid questions like "did you get the old parts back" or "do you have proof of what was replaced", because it seems weird that this shop replaced a bunch of items and only now claims the fans are an issue...... at least to me.

 

[TurboABA]

FYI:

The early 1 piece unit is (VW# 1k0254706L) and the later 2 piece units are (cat/DPF: VW# 1k0254705g and NOx filter: VW# 1k0254401t).

 

[oilhammer]

The 2009s got the two piece units installed as part of the Dieselgate fix, as the deNOx catalyst gets changed, and the only way to do that was to also replace the DPF assembly.

Unless the OP's 2009 was never fixed. In any event, fixed or not, the DPFs still fail (just more often post-fix), with the ubiquitous sooty tailpipes. I see those constantly, have one here now.

 

[Teamzarz]

necrobump, @oilhammer have you ever seen a 2009 that won’t regen because the ECU cannot be told that the DPF is new? Mechanic is stating that it won’t allow them to reset for adaptation.