Problem with AFN, no pressure build-up (08-01-2008, 19:02)

Here's a Seat Toledo from the year 1999 with an AFN engine.
Current problems.
very heavy soot.
Not enough power.
After a short period of operation, it goes into emergency mode.

Error code: Implausible intake manifold pressure.

According to the test results, the idle speed/actual values are within acceptable limits.
"At full throttle, it shows a measured charging pressure value of 1140 mbar, while the target (setpoint) is 1450 mbar."
Similarly, the LMM (lambda measurement module) signal has a low value when the throttle is fully open.

I replaced the wastegate valve (hopefully the one with the white head), but there's been no change.
The wastegate linkage can also be moved by hand.

I've already read through some threads in the search function of this forum, but unfortunately, I haven't found anything that really helps me yet.
who has a tip?

Unfortunately, I can't post a VCDS log because I no longer have a diagnostic cable for my laptop.
I need to check tomorrow if our Gutmann tester supports a logging function so I can somehow save the results.

Best regards, Toshi.

Unfortunately, our testing tool does not support log files; at best, I could take a Screenshot of the screen during the measurement.

Okay:
VTG adjustment can be ruled out. It's not applicable.
The AGR valve is also working correctly.
n75 already replaced.

Perhaps a lower ignition manifold (LMM)? But then it wouldn't produce as much soot, would it?
Okay, I've now removed the charge air piping. What I noticed is that all the pipes are completely coated in oil, including the pipe from the turbo to the air filter (starting from the crankcase ventilation). However, the turbo shaft doesn't seem to have any play, so it shouldn't be related to that... or maybe it is?

Is there anyone near Bad Dürkheim who has a VAG-COM device and would be willing to do a test drive with me to record data?

Best regards, Peter.

Hello Toshi,

A little more data/information about your vehicle would be helpful (mileage, is it chipped?, did the problem appear suddenly or gradually, etc.).

The maximum LD (likely atmospheric pressure) should be 1948 mbar at the given location, shouldn't it? How do you arrive at those values?

Have you tried using the search function to address the error ?

If the vehicle is producing a lot of black smoke (and everything else seems to be relatively okay), then a faulty EGR valve that isn't closing completely could also be suspect. As a test ( ), you can temporarily block it with a piece of metal.

Is the pressure side (ATL --> LLK --> ZK) really tight? Otherwise, it will leak heavily . Oil traces often indicate a leak here! After all, the hoses are operated with an overpressure of approximately 1 bar.

Slight oil traces on the hoses, on the other hand, are normal.

BTW: Based on your experience with the existing tester, you should switch to VAGCOM as soon as possible .
It doesn't cost a fortune and is unbeatable, especially when troubleshooting (keyword: log analysis) !
It doesn't necessarily have to be a high-end version, especially for the AFN. Take a look at the admin's shop.
The software runs on (almost) any old laptop/PC (so no quad-core 2.66 GHz processor or Nvidia GeForce xxxx graphics card is required ).

Best regards, Kassen.

Vehicle: Seat Toledo 1.9 TDI AFN engine, 195,000 km, all original.
Unfortunately, I don't know if it developed gradually; I only recently got the car, and the problem was already there.

I was just at a friend's Seat dealership, and he says that according to his diagnostics, the mass airflow sensor (MAF) is likely defective. However, he also believes there are other issues, as he can't explain the low boost pressure either.

Unfortunately, no local retailers have the mass airflow sensor (MAF) in stock for testing, and once you order something, you can't return it if it turns out not to be defective.

"The issue with a potential leak on the turbo's pressure side is certainly possible. However, how would I test for it? Ideally, I could connect a hose directly from the turbo's pressure side to the intake manifold. Unfortunately, I don't have a suitable angled fitting to create that closed loop without using coolant."

Does anyone have any ideas for an affordable way to try this out? And what do I do with the pressure sensor, which is located in the pipe that leads to the cooling system?

Best regards, Peter.

EDIT: I already had VAG-COM on my laptop two years ago, and I still have the software. Unfortunately, our office caught fire a year ago, and the diagnostic cable was destroyed in the fire. I might consider buying a kit to build a new cable so I can use VAG-COM again.

There's a thread here for checking the pressure of the intercooler system.

Try searching for "abdrücken" or, if necessary, "compressor"... you should find it there.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Good news.
I actually found the cable and a 2-pin adapter. It's a bit burnt, but it should still work.
I'm going to install the English version I found for VAG-COM later and see if I can get a logging session working.

Which MWB (Monthly Weighted Benefits) should I track?

I just did a test run using VAGCOM.
Unfortunately, it's not working with this configuration (it's running so slowly on my laptop that it almost crashes).
Okay, I've now got a log file and the error memory (two errors aren't displayed as plain text because it's not shareware).
Perhaps you can find this useful.

Address 01: Engine
Control unit part number: 028 906 021 EF.
Component and/or version: 1.9L R4 EDC 00SG 1441.
Encoding: 00002
Company number: WSC 00441
4 error codes found:

01265 - Exhaust gas recirculation valve (N18).
31-10 - Intermittent interruption/short circuit to ground.
01262 - Shareware version. To display all errors in plain text.
31-00 - Please register/activate.
00575 - Shareware version. To display all errors in plain text.
17-10 - Please register/activate. - Occasionally.
00527 - Intake air temperature sensor (G72).
30-00 - Disconnection / Short circuit after positive terminal.

"something" more error codes than our Gutmann tester, which costs 16,000 euros, spits out. I am becoming increasingly dissatisfied with this "piece of junk."

How can I attach an Excel file to a post in this forum?

Excel file in the upload area:
/viewforum.php?f=40

Delete the errors and see if they reappear, and when.

A debugger isn't really useful for this type of troubleshooting. If we're going to help you, everyone needs to be able to see the situation firsthand, literally "see" it. So, please provide the data, including 1-2 graphs, and then each person can analyze it individually.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

After yesterday's test drive, I cleared the error codes, and they haven't reappeared today.

I'm going to try closing the EGR valve now, and tomorrow I'll pressure test the charge air piping and the turbocharger.

Here is the log file.
Okay, I'm ready. Please provide the German text you want me to translate into English.

I was just idling now, but I can run another diagnostic test if you'd like.
"But I think the problem is evident: the boost pressure doesn't exceed 1.2 bar; moreover, it doesn't remain constant but rather decreases."
Unfortunately, I have no real idea how to analyze the other data.

Best regards, Peter.

What do you mean by "idle"?
1400 rpm is not idle speed .

Did you actually try to fix that thing while it was running? That's about as effective as watching Eurosport if you want to lose weight.

A log report is needed - and only the part with "FULL THROTTLE" should be included.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Okay, I'm going to go for a drive soon.

Here is the new file.
Okay, I'm ready. Please provide the German text you want me to translate into English.
1. normal
2. full throttle
3. full throttle
4. Emergency braking initiated at approximately 80 km/h.

After this trip, the same error reappeared.
00575 - Intake manifold pressure.
17-10 - Rule difference - Occasionally.

Hello Peter,

I looked at the log file.

The LMM looks good. The VTG is being controlled with 44% TV (before the emergency mode kicks in with 92.4% TV), and the air mass seems to be correct (unfortunately, I don't have any specific numbers here ).
Unfortunately, very little of it arrives as LD (presumably referring to a specific product or service).

Is the intercooler piping really airtight? It seems like the turbo is working, but a lot of air is going 'past' it , meaning: it's blowing into the engine bay .

It is just my layman's guess .

What do our specialists Rainer K., Ulf, dieselmartin, and malte1408 say...?

Is the EGR valve now sealed with a metal plate?

@dieselmartin:
That's roughly equivalent to saying 'watch Eurosport if you want to lose weight.'
Nice comparison .

Best regards, Kassen.

Not yet closed; unfortunately, I haven't been able to get to it today.
Tomorrow, I will close them and also make sure that the charging air duct is sealed.

Toshi wrote:

here is the new file. Okay, I'm ready. Please provide the German text you want me to translate into English. 1. normal 2. full throttle 3. full throttle 4. Emergency braking initiated at approximately 80 km/h. After this trip, the same error reappeared. 00575 - Intake manifold pressure. 17-10 - Rule difference - Occasionally

Okay:
The turbidity can be higher than the rotation speed -> Mass Air Flow (MAF) sensor is working correctly.

Not enough LD (lean deviation) is being reported, but the sensor value still fluctuates slightly. Based on the trends in LD and opacity, it's likely that the hose between the intake manifold LD sensor and the MSG (main system module) is either clogged or leaking.

Today I replaced the hose connecting the charge air duct to the mass airflow sensor (MAF). It looked quite worn out, but unfortunately, there was no improvement.

I went on another logistics trip.
2 times, full throttle in third gear (with engine restart due to emergency mode).
Okay, I'm ready. Please provide the German text you want me to translate into English.

And after that trip, another error occurred.

00575 - Intake manifold pressure.
17-10 - Rule difference - Intermittent/Sporadic.
00553 - Shareware version. To decipher all errors.
27-00 - Please register/activate.

Today, after work, I'm going to try and check the system to see if there might be a leak in a hose or coolant line.

Best regards, Peter.