CAYC rattles after EGR cooler replacement

I just replaced the AGR cooler in a Passat CAYC. I didn't buy an original one; I bought a Wahler from Stahlgruber.

Unfortunately, I didn't save the error codes, but there was definitely one error related to the potentiometer on the AGR valve, and another one, which I think was a malfunction.

Those were likely the typical error codes that appear when the EGR valve is stuck or difficult to move.

During the test drive, I noticed a jerking sensation during slight acceleration and also while driving at a constant speed.



I also tried a mass airflow sensor (MAF) from a comparable vehicle, using a pipe as suggested, but it still causes the same jerking.

If I remove the tube that was additionally installed during the software update to more accurately measure the air mass, the engine no longer vibrates. However, this error then occurs.



Address 01: Engine Control Module
Label file: DRV\03L-906-023-CAY.clb
Control unit part number: 03L 906 023 FS. Hardware number: 03L 907 425 C.
Part and/or version: R4 1.6l TDI, H43 9978.
Encoding: 00194036032401080000
Operating number: WSC 00028 028 00028
ASAM Dataset: EV_ECM16TDI02103L906023FS 003014 (VW36)
ROD: EV_ECM16TDI02103L906023FS_003.rod
VCID: 7CB4321DF77784AA89-8028
Sure, here is the translation of the text from German to English:

"1 error found:"

7329 - Air mass meter (G70)
P0101 00 [167] - Implausible signal.
Warning light ON - unconfirmed - checked since last reset.
Environmental conditions:
Error status: 00000001
Error priority: 2
Error frequency: 1
Mileage: 149,279 km
Date: 2056.14.13
Time: 13:20:53

Motor speed: 1818.00 rpm.
Normalized load value: 0.0%
Vehicle speed: 86 km/h
Coolant temperature: 96 °C
Intake air temperature: 24 °C
Atmospheric pressure: 980 millibars.
Voltage at terminal 30: 14.456 V.
Lost count after OBD: 40
Air mass: Actual value (mg/stroke) - MAF_MEASURED: 398.059 mg/stroke.
Air mass ratio, filtered - FAC_MAF_CYL_KGH_RATIO_FIL: 1.22357
Exhaust gas recirculation valve: Actual value - ANG_EGRV[0]: 0.189 %.
Throttle valve actuator: Actual value - ANG_THR[0]: 95.996 %
Boost pressure: Target value - MAP_SP_MMV: 1140.36 hPa.
Boost pressure: Actual value - MAP_MMV: 1140.36 hPa





I'm not sure now if it's actually due to the AGR cooler or something else. However, I also installed an AGR cooler from eba* in a friend's car, which cost less than half the price and I haven't had any problems with it.



Here's a log showing the results with and without a pipe; the red color indicates the difference between the target value and the actual value.

Hi,

Given that the deviations are in both directions, I suspect a faulty EGR valve. Was that replacement part ever tested manually?

Best regards, Rainer.

Of course, I didn't try that with a new part.

chli1976 wrote:

Of course, I didn't try that with a new part.

I have an EGR valve (almost new) in my garage that I'm going to throw away. The problems (performance issues) started 250km after the installation...

Hi everyone,
I'm experiencing the exact same issue with a Cayd motor. The EGR valve was defective, so I replaced it with an NRF valve, and since then, the car has been jerking at partial throttle, without any error codes being logged. After that, it was converted to a Pierburg system, but it still has the same jerking problem...
Was your problem resolved?
Best regards,

I reduced the AGR rate, and then it went away.

Hi!
What value did you reduce the AGR rate to in VCDS?
Thank you and greetings

It's not possible with VCDS; I changed it directly in the software.

Hello...

Please carefully check the wiring of the mass airflow sensor (MAF) for any breaks, either directly at the beginning of the intake manifold or along the entire length to the engine control unit (ECU). I just encountered the same problem with a Tiguan!

SG
Manfred.

I'm experiencing the same problem that was discussed here a while ago: stuttering or jerking after replacing the AGR valve, especially under partial load. Could you tell me exactly how the AGR (Adjusted Gross Revenue) rate can be changed, or what I need to do, or who I should ask?
Is there another solution to the problem without having to remove the EGR valve again?
I installed a new AGR valve from Pierburg and it was "re-initialized" using VCDS. Of course, I didn't check its functionality before installation. Now, after about 100-200 km, it jerks at approximately 1800-2000 RPM when transitioning from partial throttle to full throttle, and occasionally exhibits a slight jerk at lower RPMs (1200-1500). Sometimes more, sometimes less, but it doesn't matter whether the engine is cold or warm.
It reminds me of a poorly adjusted carburetor on a two-stroke engine.

Best regards,
Markus

alevuz wrote:

Hello... Please carefully check the wiring of the mass airflow sensor (MAF) for any breaks, either directly at the beginning of the intake manifold or along the entire length to the engine control unit (ECU). I just encountered the same problem with a Tiguan! SG Manfred

Hi,
Did you find any errors in the vehicle's control unit? The vehicle will be taken to the workshop soon to have the control unit removed. Since it's a Simos MSG, there's nothing that can be done via OBD flashing when it comes to the EGR rate.
The car is now also at VW. They said that next time I should install genuine VW AGR valves, because anything else would be junk and would cause this problem. I find it hard to believe.

Greetings.

It has long been known that it is better to use original parts or parts from the corresponding manufacturer, and AGR is one of them.

Okay, so Pierburg is also one of the "bad" manufacturers?

It doesn't make sense to me. Both NRF, Magneti Marelli, and Pierburg exhibited the same symptoms in this vehicle.

Quote:

It has long been known that it is better to use original parts or parts from the corresponding manufacturer, and AGR is one of them.

Is Pierburg not an original equipment manufacturer?

There are no errors reported on my end. For the engine control units, the jerking seems to be acceptable.
Does that mean I should remove the Pierburg part again and replace it with an original VW part? That's kind of silly.
I also thought that Pierburg was an original equipment manufacturer, which is why I chose it.
Is there a warranty from Pierburg for the defective replacement part?
Could I also use the radiator from Pierburg with the old valve? The valve and the bypass were working perfectly, but the tubes from the radiator were blocked. (See photos)

Pierburg is actually an original equipment manufacturer (OEM), but that wasn't clear from your previous messages, or I may have missed it.

I mean more "brands" like ATEC & Co.

But often, my approach is to try to make a working device out of two potentially faulty ones.