Caddy 2K running poorly, 1.6 TDI CR, CAYD, 102 hp

Hey,

I'm having a problem with a 2012 Caddy 2K facelift model with a CAYD 102PS common rail 1.6 TDI engine and a 6-speed manual transmission.

Vehicle Identification Number: WV2ZZZ2KZCX139661
2.1: 0603
2.2: AVE003189
Euro 5.

The problem is that the engine currently starts normally, but as soon as you briefly press the accelerator, it starts shaking, sometimes to the point where it stalls. It only revs up if you immediately give it full throttle after starting, and even then, it does so very poorly. However, it runs smoothly on all four cylinders, so there are no noticeable misfires.

The behavior improves once it warms up, or if you run the auxiliary heater beforehand.

Driving is possible, but it has very little power.

The fault memory is currently clear (VCDS).

The following items have already been exchanged:
1. Diesel particulate filter + differential pressure sensor (G505).
2. Oxygen sensor.
3. Pressure transducer.
4. Exhaust turbocharger.

Initially, after the pressure sensor was replaced, an error message appeared indicating that the boost pressure limit had been exceeded or something similar, which is why the turbocharger was replaced.

I have already checked the air filter and the fuel filter.

Current assumptions are:
Air mass flow meter G70.
Boost pressure sensor G31.
Fuel metering valve N290.
Fuel pressure control valve N276.
Fuel pressure sensor G247.
Injectors.
Or maybe even the control unit.

When removing G247, N290, and N276, it simply turns off, and I'm not sure if that's helpful.

"But now I'm starting to run out of money, and I'm hesitant to replace parts without knowing for sure if they're the problem."
Unfortunately, I lack experience with common-rail systems, so I'm turning to this forum for help.

The vehicle was purchased with this issue, unfortunately without any further documentation regarding what attempts have already been made to fix it.
Mileage: 300,000 km.

I would be grateful for any suggestions on what else could be checked.

Please accept my apologies for any errors.

Hi,
Please perform a vehicle scan and post the results here.
And most importantly (my humble advice), stop throwing blame after the fact. None of the replacement parts fit, and the suspected candidates are unusual.
It appears to be a problem with the cable, connector, or sensor, but it needs to be localized.
hg
Herbert.

Hey,

Okay, those parts were already replaced because they were defective, and I was hoping they were the root cause of the engine's poor performance. The pressure sensor was leaking, and the turbocharger's shaft was difficult to turn. The engine control unit has been reporting issues with the diesel particulate filter since the beginning, and I actually only replaced the oxygen sensor as a precaution.

I'm going to run another current car scan tonight.
Are there any values that we should log that would be helpful for further narrowing down the problem? By the way, the AGR valve has already been blocked with a blind plate to rule it out as a cause. I'll probably have to take them out again tonight, since the problem isn't related to that.

Please run the Autoscan without clearing any errors, especially after a "shutdown."

Herbert.

There are no errors in the text you provided, which is my problem and why I'm so desperate.

If I understand correctly, it's performing so poorly that it's not even delivering half of its capacity. That means, even without the turbo, it should perform better.
That is to say, for now, we don't even need to look at the boost pressure. It's enough if we just look at the amount of air and the amount of fuel. Therefore, please log both of the following (LMM should/is and fuel should, and the fuel limiting fields).
Once, while idling, suddenly floor the accelerator (and let the engine stall). And once the vehicle is in motion, this allows for a better examination of the static full-throttle scenario.

It feels like it's clogged, and it's definitely operating at well below 50% of its capacity.
I performed an Autoscan before starting and after the run, and the results are attached. I've noticed that since the turbo was replaced, the engine no longer stalls at idle. That's the only thing that has improved.
The temperature in the hall was 9 degrees Celsius, if I recall correctly.
It started normally and ran smoothly during the initial warm-up. When I slightly pressed the accelerator, the RPM dropped to just above 500 and it ran there for about 2-3 minutes (during which it would occasionally stall), and it wouldn't accelerate at all. After those 2-3 minutes, it seemed to recover and ran normally at idle again. Gas intake up to approximately 2200 RPM, but very sluggish, yet no error messages are displayed.

I will conduct the test drive with the required logging tomorrow or the day after.

Thank you very much for your help!

Hi,
Strange diagnostic scans. The overview shows an error code 0010 for module STG09 (central electronics), but when you look at the details for STG09, there is no further information. That won't work; the HEX-NET2 probably isn't picking up everything.
If you perform the diagnostic drives suggested by Guste, please also create a complete snapshot (of the extended measurement values) of the engine control unit (ECU) while the engine is idling. Save it as a CSV file! That gives us a complete set of all the measurements.
hg
Herbert.

Okay, I finally managed to get some logs while the engine was idling and at full throttle while stationary.

If any values are missing, please let us know so we can obtain them!
Unfortunately, the control unit does not have any MWB (0), but only the required ones. Measurements.

The files were recorded with the engine idling, then the accelerator pedal was fully pressed, held briefly, and then released, and the recording was stopped.

I noticed that the torque limit, specifically the "clutch protection" limit, drops to around 54 Nm after full throttle. I think this might not be normal, but what triggers this limit?

Herbert wrote:

Then, please also create a complete snapshot (of the extended measurement values) of the MSG while it's idling. Save it as a CSV file! That gives us a complete set of all the measurements.

Herbert.

Okay, can someone please explain to me the best way to do this? I've tried using the adult version. I haven't worked with the measurement data much yet, and I miss the data acquisition system!

Sure:
Main Menu > Applications > Control Unit Diagram >
- Select STG 01 motor.
- Check the measurement values.
- Check the CSV file.
> Start

You then provide us with the CSV file (located in the log directory).
I transform the data in Excel (which you can also do separately), and within that, we find all the measured values, currently, and identify the specific ones for future records.
hg
Herbert.

Copies have been made.
Thank you for the instructions!

Hi,
With the help of one of the images, you can now easily prepare further recordings as needed.
Simply change the CSV file to a text file (txt) and import it into Excel using the "text to columns" feature. For simplicity's sake, I will refer to the table rows below.
For the next recording, simply find the required lines at your warm desk, and you can then quickly select them in VCDS/Extended Measurement values using the IDE values in the first column, without having to search extensively.
Example of idle state:
Lines 11, 12, 56, 57, 58, 59, 105.
Example: Air volume, fuel volume (see). Post from Guste above:
Lines 11, 20, 23, 30, 36, 39, 42, 50, 51, 106.

You can save this selection in the VCDS menu, with the control unit open, as your own template with the *.u01 extension. The templates are located in the VCDS "Scaling" folder.
You can create your template directly at your desk. Create a new text file in the editor, enter the IDE values of your choice line by line, save the file, replace the ".txt" extension with "u01", and save it in the "scaling" folder. Important:
- line-by-line entry with line wrapping at the end of each line.
- complete IDE entry (e.g., IDE00475-ENG99518 for the fuel pressure regulating valve, table row 108),
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I will get to your data in the next post.
hg
Herbert.

What I notice in your images:
You recorded them in the following sequence: ignition on (1), idle speed 500 rpm (2), idle (3), and full throttle (4). And you did this after line 16, without interrupting the engine running? How did you get away from (2)?

In (2), the motor seems to be running on battery voltage (as you can see in lines #9 and #10), even though the generator is operating at 100% load (#63). The average injection volume is 15 mg per stroke (#105), but the RPM is still not increasing.
I'm wondering where the actual load on the motor is coming from, and why the controller isn't switching to generator mode. Rail pressure and air values appear to be normal.
In (3), things proceed normally, but what's noticeable is the imbalance in the fuel injectors (lines #56 - #5). This might resolve itself as the engine temperature increases. In my opinion, it's not the main problem either.

The particulate filter is no longer new, with 40 grams of ash (was it properly reset after being replaced?). I don't have a reference value for the differential pressure when the engine is running at full throttle while stationary.

My suggestion:
- Fully charge the battery;
- a log recording showing the following sequence: ignition on, starting, normal idle, rough idle, with the following values: #9 - Voltage at terminal 15, #10 - Voltage at terminal 30, #11 - Engine speed, #23 - Engine torque, #30 - Actual fuel high pressure, #36 - Desired fuel high pressure, #39 - Actual air mass, #42 - Desired air mass, #63 - Generator load, #105 - Average fuel injection quantity;
- Repeat with a warm engine.
hg
Herbert.

Thank you for your help!

After starting the engine (from position 2), it initially stalls, but after about 1-2 minutes, it restarts and runs normally, with a normal idle speed.

I'm still not entirely sure why that happened, but it only seems to occur once before the device reaches a certain base temperature.

The new DPF has now been installed for a while. Around November, and I believe no "automatic" regeneration has occurred since then, as the car has mostly been sitting in the workshop, and test drives were usually cut short after about 2-3 kilometers.
The differential sensor was also replaced with a new, original Bosch part. The DPF and the differential pressure sensor were reset to their default settings.

The DPF (Diesel Particulate Filter) was also replaced, as this was likely the breaking point for the original owner. Since it could no longer be regenerated, and I believed that this was the only problem, I replaced it.

I will also double-check the ash content.

Should I reinstall this component until the problem is truly resolved, or is a forced regeneration sufficient?

The battery should be okay, but I'll check it again just to be sure. It's the mechanic's car.

But does the generator actually work at such a low speed, below 500 RPM? The charging indicator light remains off during this time.

Otherwise, I will provide the requested log.
to carry out this week.

Thank you!