2.0 TDI CRLB nimmt sporadisch überhaupt kein Gas an | Posts 16+

Ste.Bo wrote:

Herbert wrote: Hi there, a) Write to Volkswagen customer service. b) Having car insurance legal protection and forcing acceptance of orders. If the TPI exists (obtainable through Erwin, see error database), customer orders (billed to account) cannot be subject to preconditions. hg Herbert . Danke für den Tipp!

Which workshop did we end up choosing?

Thank you.
Greetings.

KruSan wrote:

Ste.Bo wrote: Herbert wrote: Hi there, a) Write to Volkswagen customer service. b) Having car insurance legal protection and forcing acceptance of orders. If the TPI exists (obtainable through Erwin, see error database), customer orders (billed to account) cannot be subject to preconditions. hg Herbert . Danke für den Tipp! Which workshop did we end up choosing? Thank you. Greetings

Hello everyone,

Please excuse the lack of updates. Things have been very busy.

Die Odyssee geht weiter.

So, we found a small Volkswagen dealer who was willing to take on the car without much discussion.

He thoroughly checked the car and found nothing unusual. The software update was installed without any discussion, for a reasonable price of €120. In return, the car was freshly vacuumed and washed before being handed over.

Three days later, the problem reappeared on the A8 highway between Karlsruhe and Stuttgart, during the ascent of the Alb mountain range. The car stopped accelerating. The engine check light remained off, as with the old software. It downshifted gradually through the gears to second gear, and finally managed to limp into the next emergency stopping lane at a speed of 35 km/h.

After 10 minutes, the car started again and could be driven normally...until we reached Eichelberg. Then the same thing happened again.

I was hoping that with the new software, I would finally be able to read out a stored error code the next day. Unfortunately, there was nothing in the error memory. I took it for a test drive and logged all temperatures and shutdown parameters. Nothing. It couldn't be reproduced. Everything was within the normal range.

Back at the friendly workshop, the mechanic had driven the car on the highway with the problem, but without any findings or incidents. Back in the workshop, they searched for exhaust gases in the cooling system as a precaution... and found them. After further investigation, the EGR cooler was replaced, which actually had a visible crack. Afterwards, no more exhaust gases could be detected in the cooling system.
Everyone believed they had found and fixed the problem. The following weekend, the family took their car on a vacation to Croatia. In total, it broke down three times! On one particularly hot day (38°C), even trying to cool things down didn't work, and they had to be towed.

The ADAC partner and corporate contract workshop insisted that the DPF had reached its loading limit, even though there was still over 20% "space" until the limit, and I had not detected any unusual pressure differences or regeneration cycles 10 days prior.

Out of desperation, an exchange was agreed upon. So, I spent my vacation with a rental car that was too small, while the Passat received a new DPF (Diesel Particulate Filter) and differential pressure sensor.

Die Hoffnung, dass nun alles gut sein könnte, zerschlug sich kurz nach Zadar auf dem Heimweg beim Autobahnaufstieg Richtung Sveti Rok. Everything is as usual.

Since the car has been within my reach again, I haven't been able to reproduce the problem, because even when fully loaded, the error doesn't occur on very long inclines if the temperature is above 25°C.

My sister is desperate, and I'm starting to feel lost for what to do as well. We're going to swap cars next week so that I have more time to try things out.

Okay, so if anyone has any brilliant ideas on this topic, I'm open to any suggestions.

Best regards,

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

I would check if the engine control unit (ECU) responds normally to diagnostic messages in case of an error (i.e., no resets of the ECU, connection interruptions, etc.).

Using an STM32 evaluation board, send a CAN or OBD-2 message. If a response is received, the LED should turn green; if there's a timeout, the LED should turn red.

More manageable effort

dieselschrauber wrote:

I would check if, in the event of an error, the engine control unit normally responds to diagnostic messages (i.e., no resets of the ECU, connection interruptions, etc.). Using an STM32 evaluation board, send a CAN or OBD-2 message. If a response is received, the LED should turn green; if there's a timeout, the LED should turn red. More manageable effort

.

Thank you.

To do that, I need to be at the car when there's a problem, before someone turns off the ignition.

I will remember that!

What's the underlying idea here? It seems to only happen with higher ambient temperatures and a high load sustained for several minutes. I've almost ruled out a control unit malfunction. Right now, I'm thinking it might be related to the wiring harness, but where do you even start looking? Especially since the car isn't giving any specific error messages.

Regards,

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

Hi,

The device can always be connected to the diagnostic port. Turn off the ignition, and if there's no response from the ECU after a few seconds, assume it's not working and just ignore it for now.

If the ECU malfunctions or loses power, you will see this reflected in different response times to requests sent via CAN.

Das Gemeine bei Problemen mit der Stromversorgung ist, dass kein Strom zum Schreiben in den Fehlerspeicher... X

Is the coolant temperature sensor and its wiring checked?
It's just that, in case of a fault, the ECU shouldn't think the engine is about to melt down immediately.

Best regards, Rainer.

dieselschrauber wrote:

Hi, Das Gemeine bei Problemen mit der Stromversorgung ist, dass kein Strom zum Schreiben in den Fehlerspeicher... X M. Best regards, Rainer

Yes, but wouldn't that cause the box to shut down? The injector driver stages receive the same power as the memory.

dieselschrauber wrote:

Hi, ... Is the coolant temperature sensor and its wiring checked? It's just that, in the event of a fault, the ECU shouldn't think the engine is about to melt down. Best regards, Rainer

Yes, multiple times, and not just by me.



Then I'll see when the lady goes on her next trip so I don't need this stuff anymore.

Thank you!

Quote:

Ja, aber würde die Kiste dann nicht ausgehen? Die Injektorendstufen bekommen doch den gleichen Strom wie der Speicher.

Only if the power outage lasts longer. I've already experienced cases where the ECU reset permanently and the engine continued to run erratically.

In this case, the problem was caused by severe electrical system malfunctions due to a faulty fuse box (which had nothing to do with the ECU).

Therefore, it would also be great if any disturbances in the onboard voltage were displayed as well.

It's strange that the software update didn't fix it. Have you checked it? Is the control unit really reporting as 04L 906 026 AT now?

It seems that the MSG is receiving power (otherwise the motor wouldn't be running at 1500 RPM), but it's still not logging an error. I can hardly explain such a drastic reduction in performance at 100% driver demand without any error message being recorded. Possible causes that come to mind are:
1) Gas pedal
The accelerator pedal itself could theoretically also be the cause of the problem. However, it is designed with redundancy and monitoring systems. I can't think of any reason why, despite this redundancy, it would only exhibit a synchronous failure under load.

2) Brake pedal / brake pressure sensor:
Wenn das ABS/ESP einen Bremseingriff bemerken würde oder einen Regeleingriff an das MSG übermitteln würde, dann gibt's ebenfalls keinen Fehlereintrag. Aber was da unter Volllast passiert ist für mich fraglich. Was du aber schreibst: Es passiert immer bergauf. D.h. mit abnehmender Luftdichte. Wenn du irgendwo Luft im System hast, würde sich die ausdehnen. Mit viel Fantasie könnte man sich da etwas zusammen spinnen. Einmal Bremsflüssigkeitswechsel könnte eventuell nicht schaden und kostet kaum. VerI don't talk about much of it, though.

3) Clutch pedal sensor.
If it's a manual transmission: I'm not sure if it also limits the power. It's quite possible. But I've been driving automatics for too long. However, even here: It's strange that the sensor would only falsely report pedal pressure under full load.

4) DSG: Wird ebenfalls heiß und könnte Drehmomentreduktion anfordern. Ggf fälschliche Gangwechselanforderung mit entsprechender Momentenreduktion. SeIt is questionable.

5) A faulty MSG (Motor Signal Generator), which is no longer correctly processing certain inputs or messages. The MSG is located in the engine compartment and also gets hotter than normal under full load (due to engine heat, not due to power demand itself). In this case, either the MSG can be replaced, or it can be externally heated.

Many wild theories, some of which I find highly questionable myself. But perhaps you'll find something thought-provoking among them.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

Possibly, in the event of a fault, the fuel temperature may become hotter than usual, and there is a crack in one of the plastic parts on or near the diesel filter, or possibly the "Knackfrosch" (a specific type of component).

A piece of transparent fuel line connecting to the pump at the filter provides clarity.