01268 Quantity setting (upper limit) error, likely found

Memory error: 01268. Quantity setting: 35-00-.
including a flashing preheating lamp (after replacing the control unit with a newer version that includes the 'upper limit' feature).
Symptoms: Jerky performance at partial load.
Previous repair attempts: VEP (voltage regulator) replaced (2 times), control unit replaced (3 times), cables checked (partially repaired), fuel injectors (specifically NHG type) checked, relays and fuses, etc. checked.
Result: no change.

What else could cause this error? Which components that are not likely to be the source of the error are still potentially relevant? Does anyone have any other ideas?

Okay, I'm ready. Please provide the German text you want me to translate.

-> Search function & expert articles!
--> Search: 'rough idle'

Quote:

Code: Was war Ihr ursprüngliches Problem: "Ruckeln im Leerlauf"? No. The problem, as described, is with the mass airflow sensor, which cannot be resolved by replacing the pumps or control units. The engine always stutters. There's fluctuating idle speed and hesitation during acceleration in all gears. Besides the full-throttle mode, I said "partial load range." Code: What car model and engine code are you referring to? It should always be included. Passat 3B, year of manufacture 1998, engine code AHU. My mistake. Code: Have you accepted Julian's search recommendation, and what conclusions have you drawn from the articles you found regarding the potential cause of the stuttering? I've been searching

like crazy. But since the pump and the control unit are new, and we've checked the cables, fuses, injectors, etc., I unfortunately can't find a suitable solution. (which I've already said ).

It looks like there might be a problem with the cables or connectors between the control unit and the fuel injection pump.

Thank you, Rainer. We have, of course, already checked the cables. Also the connectors. We performed resistance measurements and checked for short circuits. No errors could be found. We also stripped the entire outer insulation up to the control unit and checked everything. The needle lift injector was disconnected: This resulted in a limp-home mode and an error entry. Nozzles tested: all within the normal range.
Battery disconnected for several hours: Strange and very confusing result:
The error could be cleared, and the engine ran for a while without the flashing preheating indicator. Turning off the ignition and restarting the engine brought the error back. This action could not be reproduced. The error also occurs with a brand new control unit.

Regarding the error entry: The error is not sporadic, but persistent. In the search , I found references to adjusting the pump and other interesting things. However, since the error also occurs with other pumps and control units, I am (almost) ruling that out. Diagnosis and inspection were performed at VW , but they were also at a loss. The 3 cables to the connector (valve for injection start, etc.) were repaired using crimps because the technicians ripped them out of the connector when disconnecting them. A small damage to the outer sheath was also repaired. Otherwise, there are no errors or anything similar to be found .
One idea was related to a potential diesel shortage, which I would also like to (almost) rule out. The diesel system was just completely overhauled. The diesel filter is almost new.

The car was in the workshop for a fuel pump replacement because the fuel injection timing valve was defective. The entire pump was replaced. However, the problem was already present before the car left the workshop. Even after replacing the pump and control unit again, there was no improvement.

The 3 cables to the connector (valve for injection start, etc.) were repaired using a crimp connector because the guys ripped them out of the connector while disconnecting them. A small damage to the outer sheath was also repaired. Otherwise, there are no errors or anything similar to be found .

I think you've made a mistake there...

I would insist on a new engine wiring harness (of course, free of charge).

Is there a backstory to this error?

CU Gremlin.

mullemaus wrote:

Memory error: 01268 Quantity setting 35-00- including a flashing preheating lamp (after replacing the control unit with a newer software version that includes the upper limit feature)

Then, read the upper limit value and compare it to the target value according to the table.

If a target value is not listed for your engine, you may need to refer to the specifications of engines that are as similar as possible.

I think you've found your mistake... I would insist on a (of course, free) new engine wiring harness...

What incredibly confuses me is the situation with disconnecting the battery and the subsequent (temporary) functioning . The cable only has an indirect connection to the fuel quantity control (injection start valve), or does the potentially altered line resistance there have an effect on the fuel quantity control? Okay, I'll take a picture of this shoddy workmanship.


Is there a backstory to this error?

I already sent that to you earlier .

I will do the data extraction.

Here's the photo. The arrow points directly to the location of the damage to the outer layer (usually, this would be patched with electrical tape).

http://img146.exs.cx/img146/6277/kabel6fo.th.jpg

@mullemaus

Please give your friend a warm greeting!

Okay, let's see what makes you so sure about the intact diesel system. Air in the diesel line would have the same effect. I experience similar issues in my oil-burning A4 when it's cold outside and I need a lot of power, especially when it's running on oil. Switching back to diesel fixes it. This could indicate an air leak. Try this: connect a clear hose from the return line towards the windshield and observe. If you see any foam, you've found the problem. Otherwise, have the injectors tested. However, it's not enough to just check the opening pressure, as TDI engines have a dual-spring injector system.

@mullemaus, please give your friend a warm greeting!

Sure, I got it. Thanks and you're welcome.

hmmmmmm... what makes you so sure about the intact diesel system?

Completed. Supply and return. Tank, etc.

Otherwise, have the injectors cleaned. However, it's not enough to just check the opening pressure here, as the TDI engines have a two-spring injector combination.

I have adjusted the opening pressure in the machine, and it seems to be correct for all nozzles. Nozzle 3 (NHG) is brand new, while the other three nozzles have been internally refurbished and tested. Before that, the people at Bosch and the 'old man' said they were top-notch.

How does this patch affect the injection start valve? Could it be related to the quantity adjuster? Higher lead resistance (purely theoretical), also later injection start, and consequently, a higher upper limit for the quantity adjuster?

hi,

Okay, so if it was working reasonably well before the pump replacement, then the pump replacement is likely the cause. The patched connections aren't ideal, but if they were done carefully, they probably aren't the problem. Where did the pump come from? From the same reputable repair company that supplied the AT engine? If it's not a new pump, that's probably the cause! Also, the injection/pumping start timing might be the issue. Have you checked or adjusted it? Valve timing is less likely. If the entire timing is off by even one tooth, the engine simply won't start.

Okay, before the repair, only the fuel injection start valve was broken. Instead of replacing the valve, this 'mysterious' company sent a complete pump. This pump was installed, and that's when this error appeared. Then, the car went to VW, and there, a 'guided troubleshooting' was performed using the 5052 diagnostic tool. The result was: replace the control unit. That's what was done (a brand new) control unit was installed, but the error was still there. A 'guided troubleshooting' was performed with the new control unit. The result was: replace the fuel injection pump. This was done immediately at VW, including adjusting the fuel injection start. Result: Error still present.
Since the control units and pumps have been replaced multiple times, but the problem still persists, we're really not sure what else to do.

Well, then things take on a completely different aspect.

Okay, so I'm going to assume that the ESP module is at least a genuine part from the Volkswagen Group (VAG) and should therefore be in working order. That leaves the suspicion of a faulty wiring harness or corroded connectors at the control unit or to the ESP module. As a temporary measure, try connecting the cable directly from the control unit to the pump...

What's actually going on with your friend's charging problem? Are you able to fix it?

So, the pump is completely from the aforementioned company; it's not a VW part. The cables were completely checked, and a separate line was also installed. There's nothing more to do. I then (unauthorizedly) made a mechanical and electronic correction. It was within the electronic limits, and we made some changes mechanically. It's a little better, but the underlying problem is still there; the jerking is just a little better. They now want to send the removed pump to an independent test bench for testing and adjustment. We're at a loss, especially since our electrician confirmed that the cables are also in good condition.

Which part could still be causing this error? One more idea (no matter how absurd)

Please describe the "ruckeln" (jerking/stuttering) in more detail: when does it occur, how does it manifest, what are the specific conditions, and what are the noticeable characteristics?

It first appeared after replacing the pump and soldering the connector/cable to the shut-off solenoid valve / valve for starting the injection process. The men probably ripped it off while trying to pull the connector apart. After it was finished, the preheating lamp illuminated, and the 'quantity regulator fault' error was stored in the memory.
The jerking occurs in the partial load range, specifically around 1000-2500 or 3000 RPM. The jerking, or 'shaking,' is already present at idle, up to the aforementioned RPM. Adjusting the mechanical settings (moving the pump housing) initially resulted in the complete opposite effect (increased jerking and vibration). When the housing was moved towards the driver's side, it subjectively seemed to improve slightly, but only temporarily. The engine seems to have less power overall. If the error is related to a second entry in the memory, it can be cleared, but it reappears after a restart. However, the jerking is persistent. Injection start is correct (5052), the electronic adjustment (Login 12233) for channel 1 is within the normal range, between 2-9mg/r, approximately 3.8-4. We adjusted it down to 2.2, but that didn't make a difference. The jerking itself is very severe depending on the gear (2nd and 3rd gear) to 'soft jerking' (around 4th gear). Conditions: Engine with approximately 11,500 km ('old'). No biodiesel. Fuel lines (supply and return) are new, including tank cleaning and fuel filter replacement. No other errors in the memory. The jerking occurs whether the engine is warm or cold.
Observation: After disconnecting the battery (for charging), the car started immediately (just by turning the key and it ran as it should for a TDI, otherwise it usually takes about 1-2 seconds of starter motor engagement), ran smoothly, and was perfect. Restarting it brought everything back to the original problem. This was not reproducible.

In addition, the wiring from VW was checked to exclude short circuits or excessively high wire resistance. Everything is in order, and no faults were found. Control unit replacement (three times, the last one was brand new from WOB) only required an additional setting in the memory: 'upper limit.'

Is the 109 relay already okay?