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Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds

Lakondziorex 11118 11
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  • #1 16804524
    Lakondziorex
    Level 12  
    Posts: 165
    Rate: 9
    Hello,
    Well, I have a problem with the turbine in Octavia 1 1.9 TDI 130 ASZ.
    At faster speeds, 150km in 5th gear, 180km in 6th gear, error 17964 charges pressure control crashes.
    The same happens when starting quickly and then in 3rd gear at 3.5 thousand revolutions.

    I replaced the N75 valve, correctly connected because the first time there was no power. Tubes are now connected according to the ASZ diagram in the label.

    Logs from 011

    The car pulls from 1800 to the end like furious But then notlauf. At the start you can feel it from 1700 sudden "kick" and then there is fire.

    Vacuum hoses checked, all tight, functional.

    Pear tested on BS 011. I checked in the channel under the samhodhod pear moves about 2cm, without slowing down.

    Can the pear stutter at higher speeds or is it rather refreshing VTG?

    Where can the cause lie? Thanks in advance.

    greetings


    Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds
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  • #2 16804538
    Doktorr
    Level 35  
    Posts: 2427
    Help: 286
    Rate: 1090
    You need to detach the pear and see if the geometry itself is very light in the entire range of work. Probably a little pruning at maximum pulled and will not manage to let go when you start suddenly or when the engine is heavily loaded.
  • #3 16804558
    Lakondziorex
    Level 12  
    Posts: 165
    Rate: 9
    Ok, but when it gets stuck, it's the turbine and the geometry to clean?
  • #4 16804574
    Doktorr
    Level 35  
    Posts: 2427
    Help: 286
    Rate: 1090
    Yes, for cleaning, and by the way it has loose axle, it needs to be regenerated.
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  • #5 16804575
    Lakondziorex
    Level 12  
    Posts: 165
    Rate: 9
    Ok, that's the topic to close. Since the rest excluded n75 and pear.

    Added after 2 [hours] 9 [minutes]:

    Is everything ok with the flow? All logs from 010 are in standards
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  • #6 16811741
    Lakondziorex
    Level 12  
    Posts: 165
    Rate: 9
    Refreshes the topic again, could it also be the fault of the boost pressure sensor? Can you check it somehow? Block 010 in vag com?
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  • #7 16865179
    Lakondziorex
    Level 12  
    Posts: 165
    Rate: 9
    Hello again, I'm cleaning the turbine geometry, the spec checked the valves all ok. As I mentioned n75 is new. Pear is like new, it works, no corrosion, new like from the box. Despite this, for example at 5 gear at high speed the engine catches notlauf. What could it be? Should I replace the MAP sensor?
  • #8 16865573
    grala1
    VAG group specialist
    Posts: 9812
    Help: 1495
    Rate: 5036
    From the log it is evident that there is an overload - the engine controller orders to cut off the negative pressure given by N75 and the pressure given by the turbine does not drop.
    It is best to connect a vacuum gauge in front of the pear and observe while driving, which shows what the vacuum is when VAG shows N75 control at 94%.
    You may have a badly connected or damaged N75, a clogged hose going to an N75 air filter, a jammed turbine.
    The fact that it has been cleaned does not mean anything - it can already be so worn that the steering wheels get hooked / blocked.
    Show block 11 on the engine not running.
    For example, you can give a longer hose from the N75 to the turbine by running it through the cabin. When reloading occurs, unfasten the hose in the cabin and the current pressure should sleep immediately. If it does not fall, then the problem is in the turbine. If this drops, the problem is on the N75 or tubing side.
  • #9 16866149
    Lakondziorex
    Level 12  
    Posts: 165
    Rate: 9
    I will do logs 11 on the engine not working tomorrow morning.

    Below I will give logs after cleaning the geometry etc. (Almost the same as before the interference), the car has a slightly better bottom (better kick) but there is reloading. The hoses have been checked and they are fine, one has been replaced. Pear on 011BS moves smoothly throughout. Her condition is perfect. The new N75 valve, the same on two valves, that's why I gave the turbine for cleaning. He doesn't have enough work space or a vacuometer. Everything has already been checked. From what I read at my uncle google, this could be another reason - MAP sensor. At the allegro I can buy one for ASZ for PLN 50. Buy one on trial? Maybe the current sensor distorts the values and everything is ok. What do you think grala1?

    Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds
  • #10 16866266
    grala1
    VAG group specialist
    Posts: 9812
    Help: 1495
    Rate: 5036
    It makes no sense to replace the MAP sensor. I don't believe its damage here.
    First of all, you can see that the measurement of pressure starts from about 1000 so as it should be.
    Secondly, damage to the sensor contradicts what can be seen in the measurements shown.
    How does turbine control work?
    The controller requires a top-up value of e.g. 2500 and will control the N75 until the MAP sensor reading appears at the value it requires. If the pressure from the sensor is too low, the N75 will open more and the pear will pull a strong barbell. If the controller sees too high pressure from MAP, it closes the N75 and the pear leaves the bar. If after that the pressure will be too high then the N75 will be even more closed and if the value read further is greater than the set value, the controller will close the N75 and then the pear will release the bar, which causes a decrease in pressure on the MAP sensor.
    Your pressure stays on all the time despite the fact that the N75 has been turned off by the engine control unit. If the driver has triggered an overcharge error, the N75 is no longer controlled and the turbine should not blow and you blow all the time.
    Since you say that N75 is functional, the hoses are not clogged, the problem lies in the turbine.
    Put on a longer hose between the N75 and the turbine and unplug it while driving as it overloads. I will show you whether the turbine blows by itself or if the pears are vacuum.
  • #11 16866299
    Lakondziorex
    Level 12  
    Posts: 165
    Rate: 9
    How to put it on to cut off the tubing while driving? How to bring a hose to the cabin? One person drives and the other has to disconnect the hose. Well, probably some connector to disconnect then right?

    Added after 11 [hours] 12 [minutes]:

    Adds 011 logs

    Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds

    Added after 49 [seconds]:

    Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds Experiencing 17964 Charge Pressure Control Crash in Octavia 1.9 TDI ASZ 130 at High Speeds
  • #12 16872006
    Lakondziorex
    Level 12  
    Posts: 165
    Rate: 9
    Could this be a problem of a badly adjusted barbell (pear)? Because I do not know if the turbo does not get up too late and later reloads

Topic summary

✨ The discussion revolves around a charge pressure control error (17964) experienced in an Octavia 1.9 TDI ASZ 130 at high speeds. The user reports issues with the turbine, particularly at speeds of 150 km/h in 5th gear and 180 km/h in 6th gear, as well as during rapid acceleration in 3rd gear. The N75 valve has been replaced, and vacuum hoses checked, but the problem persists. Suggestions include inspecting the turbine geometry for blockages, cleaning the turbine, and considering the MAP sensor's functionality. The user is advised to monitor vacuum levels and check for any pressure discrepancies during operation to identify the root cause of the issue.
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FAQ

TL;DR: Overboost (17964) on the Octavia 1.9 TDI ASZ often shows MAP starting near ~1000 mbar; “It makes no sense to replace the MAP sensor.” Focus on VNT movement, N75 control, and vacuum-line tests before parts. [Elektroda, grala1, post #16866266]

Why it matters: This FAQ helps DIYers quickly diagnose 17964 notlauf without wasting money on unneeded sensors, using forum-proven tests on VNT, N75, and vacuum lines.

Quick Facts

What does fault 17964 (Charge Pressure Control: Positive Deviation) mean here?

The ECU demands target boost, but actual boost stays too high even after it commands N75 closed. That triggers overboost and limp mode. In this case, persistent boost despite N75 cut points to VNT/turbo mechanics, not a sensor. [Elektroda, grala1, post #16866266]

Why does notlauf hit at high speed or around 3,500 rpm?

Under heavy load, sticky or worn VNT can hold the vanes too closed. Boost overshoots and does not fall fast enough when the ECU cuts N75, so the controller flags overboost and enters limp mode. [Elektroda, grala1, post #16865573]

Should I replace the MAP sensor to fix 17964?

No. “It makes no sense to replace the MAP sensor.” Readings start near ~1000 mbar as expected, and control logic shows the issue is boost not dropping when commanded, which implicates VNT/turbo control, not the MAP. [Elektroda, grala1, post #16866266]

How can I test the turbo/VNT without a vacuum gauge?

Fit a longer hose between N75 and the actuator and route it into the cabin. During an overboost event, unplug the hose. If boost drops immediately, the issue is upstream (N75 or plumbing). If it doesn’t, the turbo/VNT is sticking. [Elektroda, grala1, post #16865573]

How do I check actuator travel on the ASZ?

Use Basic Settings 011. Watch the actuator (“pear”) move its full stroke smoothly. The thread reports about 2 cm travel with no slowing; erratic or limited travel suggests sticking or misadjustment. [Elektroda, Lakondziorex, post #16804524]

What is the N75 valve and how does it control boost?

N75 meters vacuum to the VNT actuator. The ECU increases vacuum to close vanes for more boost and vents vacuum to open vanes for less. In overboost, the ECU can fully close N75, expecting boost to drop. If it doesn’t, mechanics are at fault. [Elektroda, grala1, post #16866266]

What is the MAP sensor and how is it used here?

The MAP sensor reports intake manifold pressure. The ECU compares requested vs. actual; if actual exceeds requested for too long, it sets 17964 and cuts N75. Correct baseline readings near ~1000 mbar suggest the sensor is fine in this case. [Elektroda, grala1, post #16866266]

Can hose routing or the N75 filter cause persistent overboost?

Yes. Misconnected lines or a clogged hose to the N75 air filter can trap vacuum. That keeps the actuator pulled, vanes too closed, and boost high, even when the ECU tries to vent. Check routing and the tiny filter path. [Elektroda, grala1, post #16865573]

Why log Measuring Block 011 with the engine not running?

It provides a baseline for the control values and actuator test duty without engine load. Sharing those helps spot control anomalies before chasing hardware, as requested in the thread. [Elektroda, grala1, post #16865573]

Could a misadjusted actuator rod (“barbell/pear”) cause late spool and then overboost?

Yes. Incorrect rod length shifts VNT calibration. Vanes may open too late, spooling late, then overshooting target when load rises. The ECU’s logic shows overboost if boost won’t drop after N75 is closed. Adjust only after tests. [Elektroda, grala1, post #16866266]

I cleaned the VNT but still get 17964 — what next?

If geometry is clean yet sticks under load, inspect for wear and shaft play. “If it has loose axle, it needs to be regenerated.” Rebuild includes cleaning, bushing/balancing, and resetting actuator. [Elektroda, Doktorr, post #16804574]

What edge cases should I watch for after cleaning?

“The fact that it has been cleaned does not mean anything.” Worn guides or vane pins can still catch when hot, causing overboost only at speed. That failure mimics a good bench test but fails on-road. [Elektroda, grala1, post #16865573]

How do I perform the in-cabin hose cut-off test (3 steps)?

  1. Connect a longer vacuum hose from N75 to the actuator and route it safely into the cabin.
  2. Drive to reproduce the overboost/limp event.
  3. As it happens, unplug the hose; immediate pressure drop points to valve/hoses, no drop points to turbo/VNT. [Elektroda, grla1, post #16865573]

Are my MAF (Block 010) readings likely at fault?

The poster reported Block 010 “in standards,” while overboost persisted. That shifts diagnosis to boost control (N75, vacuum plumbing, VNT), not airflow metering. Verify boost control before chasing MAF. [Elektroda, Lakondziorex, post #16804575]
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