MIL ON - Code P048C

Check Engine Light was illuminated Monday morning.

My Settlement warranty ended about 3,000 miles ago.
Bugged me the whole day.

In the evening I scanned with VCDS and got the following code:

9162 - Sensor for Exhaust Flap
P048C 00 [237] Implausible Signal

I cleared the code and it popped up about 5 minutes later.

Planned to take the unit out of the exhaust and clean the inside it up with oven cleaner.

The MIL went away yesterday afternoon.

The VW is acting like a Toyota. It fixes itself. sweet.

I may take the unit off just to do an inspection.

If it’s covered under the TDI warranty... take it in.


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That is the "it is time to delete" sign.

Sucks that it happened right after the warranty ran out, but....

At least the exhaust flap is still its own piece on the CKRA. The later cars got it integral with the exhaust pipe.

The part on your car has been improved a couple times. The current part number I think is 1K0-253-691-J and you'll likely want the two gaskets and v-band clamps as well.

Exhaust flap you say?

Boy do i have a deal for you!!!

http://forums.tdiclub.com/showthread.php?t=480015

I have been thinking of a delete weekend ever since the Settlement funds were calculated. But the break even of 50+ vs. 41 mpgs and no regens is out to about 350k miles, so it remains a wish list item.

I removed the exhaust flapper this weekend. It was squeaky clean. Literally. Of course. Post DPF all the exhaust sees is high temperatures, nox & sox free CO2 and water vapor, right?

I actuated the flapper and it would stick shut. Spraying dry lube 3-in 1 into the pivots helped decrease the stiction. I put some high temp brake lube on the pivots and worked that it. It wouldn't stick and the shaft spring was strong enough to return it to open.

This has probably all been burned out now in the 125 miles I've driven since then.

If you remove the exhaust flapper, i highly recommend you get the stainless steel gaskets (2@ $6) and the v-band claps (2@ $16). You can probably reuse the clamps but mine were stuck on with corrosion and I had to knock them off with a punch. They got a little bent, so installed the new ones I purchased from the dealership.

That assumes it will make it to 350k miles without anything breaking. It won't. It already didn't. I do not think there has ever been a 2009+ TDI that could claim that, and post Dieselgate the chances are even slimmer. Shortened turbocharger life, cracked/failed DPFs, EGR problems, clogged heater cores, SCR component failures, sensor failures, the list just goes on and on (and on, and on...). It really sucks that they cannot seem to figure the durability part out, and we lost access to these cars sadly before their teething issues could be worked out. I bet a 2020 model TDI is probably pretty good. But we'll never know here.

The CR TDIs with DPF regens may have a heat problem.
But it is nothing compared to the BMW N63 hot Vees.
How can a vehicle meet emissions and burn a quart of oil every 600 miles? That one amazes me.

While I had the vehicle up in the air, I had my wife start the car to verify the MIL light did not come on.

Also, I had her floor it a couple times. The engine would hit the rev limiter, and the exhaust flap would close (position 2).
The unit has a Position 1 and 2 on the housing. There is an indicator at the spring area to show valve position. The butterfly plate is open in position 1 and closed in position 2.

I thought this was interesting and unexpected.

It closes to force more pressure through the HP EGR to help reduce NOx.

In 2013 or so VW extended the warranty on this valve, in a service campagn.

Many people tried cleaning and freeing up the valve and it fixed the issue, but for a short period of time and the internal damage of the bushings eventually continued to chew themselves up and seize, there's a reason why there are multiple revs of the flap.

http://forums.tdiclub.com/showthread.php?t=379543&highlight=exhaust+flap

It is for the LOW pressure EGR. The high pressure one needs no extra shunting, as it already has 50% more pressure than the intake, same as all the previous TDIs.

It also has some other purposes, warm-up, regen, but its main reason for being there is to make the low pressure EGR work. Otherwise, the exhaust would just flow right on past the EGR feed tube...in fact it would actually SUCK air from the air inlet out the exhaust.

opps, I forgot HP EGR is before the turbo correct?

Yes, the high pressure EGR gets its exhaust from right out of the engine, but before the turbocharger's exhaust driven wheel. Same as the VE and CR TDIs.

Low pressure EGR, which is "cleaner", comes from after the turbocharger and more importantly after the initial catalyst and the DPF (that first catalyst is integral with the DPF, and is right out of the turbo's outlet).

This low pressure EGR has no soot (at least, not much), so is as clean as the tailpipes should be. However, because it DOES contain a high amount of H2O due to normal combustion processes, it becomes a problem for some engines with regards to intercooler icing, since this moisture which exits the exhaust pipe in 100% gas form and goes through the EGR valve and into the turbo in gas form gets compressed then allows for condensation to occur. Which of course is the act of going from a gas to a liquid, or if it is cold enough and the conditions are just right, going even further and becoming a solid (ice).

Other manufacturers are now doing low pressure EGR, I noticed the 2019+ Sprinters (which use a revised 3.0L V6 carried over from the previous generation) have employed a post-DPF EGR source. I think one of the GM diesels does too.

Similarly, many newer Hondas also tap their EGR source post-catalyst, for presumably not only cleaner but even more oxygen-depleted air. Which is the whole purpose of EGR anyway (to introduce oxygen-depleted air into the air intake charge so as to not have so much free oxygen floating around that needs to be used with fuel in the combustion process).

Update: mil light came back on. Stop and go traffic. Then I took a few quick trips. It went away. It then lit up again then went out.

I haven’t ran a scan, but I think my high temp grease was a short term fix. Maybe in July I’ll be in the market for a new exhaust system. If you know what I mean. ��

buy mine!!!

still has a nice layer of protective dust on the box, plus two gaskets!!!

http://forums.tdiclub.com/showthread.php?t=480015

Update: The CEL was on constantly. I would remove with VCDS, and it would pop up within 1 -2 days.

Purchased a NOS flapper valve from 740GLE. Thank you very much!

Installed within 15 minutes. Drove around awhile and CEL light went out. It hasn't returned.

On the bench, the old unit would stick shut. The new unit would go through full range of motion very smooth.

Hope to get many more trouble free miles out of the turbo, DPF, AdBlue, HPFP, etc.
Time will tell.

Well worth the DIY vs the dealer charging $500 for the job.

Now i just hope i don't kick myself that I need a flapper in 100K.