Error code 550 Audi A4 TDI?

Hello,

'I'm experiencing an issue with my A4 1.9 TDI/81 kW: the engine occasionally jerks briefly in the 4th and 5th gears when accelerating, starting around 4,000 RPM.'

After that, I found error code 550 in my engine control unit.

What could that be? Does anyone know this problem?

Regards,
Jackson.

00550 = Injection start control.

But without the rest of the data (which would be on the next line in VAG-COM), it's not a complete error message.

-Uwe-

Hello,

Here's the translation:

'It also states the following: 17 - 10, Rule Difference, Sporadically.'

Please use the search function; the error database isn't just there to make your backups unnecessarily large!

Okay, I will provide the translation. Please provide the German text you want me to translate.

I've already read those before, but I have no idea what could be broken.

I suspect that either the injection timing valve (N108)) or the needle lift sensor (G80) is defective. But I have no idea how to narrow down the source of the error.

Could the error also be related to the EGR valve?

Hi,

Here you can read how to test the needle lift adjuster.

/viewtopic.php?t=1712&highlight=nhg+test

Best regards, Andy.

Jackson wrote:

I have already read those, but I have no idea what could be broken. I suspect that either the injection timing valve (N108)) or the needle lift sensor (G80) is defective. But I have no idea how to narrow down the source of the error. Could the error also be related to the AGR?

Hello,

You can test the fuel injection start timing using the actuator of the engine control unit.
The engine is running in idle mode, and it periodically changes the spark advance.
Other possible causes: air bubbles in the diesel line due to a faulty fuel tank vent, leaking O-rings in the fuel preheating switching valve in the diesel filter, and a clogged (too old) diesel filter.

Check the injector with the knock test; if you hear any unusual noises, add diesel cleaner to the tank and hope for the best. Otherwise, replace the injector with a new one.

Best regards, Rainer.

Hello,

Thank you for the answers. Since my car is due for an inspection anyway, I'll install a new diesel filter and check the NHG (noise, vibration, and harshness) system with a knock test and actuator test.

But after reading everything I've seen, I think the NHG (likely referring to a specific car part or model) is probably worn out (with 150,000 km).

Let's see...

Regards,
Jackson.

Hello,

I installed the new needle valve today, but unfortunately, the problem is still not resolved!

I also installed a new diesel filter in the meantime.

I'm still encountering the following error:

'In 4th and 5th gear, when accelerating at full throttle between 4,100 and 4,400 RPM, my Audi hesitates (like it's momentarily losing power), and then I either get an error code.'

The numbers 0550 17-10 or 0550 17-00 are listed in the MSG.

What could be the reason for that?

Regards,
Jackson.

Jackson wrote:

"In 4th and 5th gear, when accelerating at full throttle between 4,100 and 4,400 RPM, my Audi hesitates (like it's momentarily losing power), and then I either get an error code." The numbers 0550 17-10 or 0550 17-00 are listed in the MSG. What could be the reason for that?

-> Air leaks in the pump inlet line due to "hidden" leaks at the filter connections.

-> partially clogged suction unit in the tank.

-> Stuck injector nozzle in the pump.

That's all I can think of right now.

In the error database, there is still information about a faulty fuel injection start valve (N108)).

Does that also apply to my error description?

'If so, where is it located?' What are the part numbers and prices?

Jackson wrote:

The error database still contains information about a faulty fuel injection start valve (N108)). Does that also fit my error description?

Hi,

That's what I meant by "injection rate adjuster."

Hello, the N108 is located at the very bottom of the ESP (Electrical Submersible Pump), where the lever for the cold start (KSB) used to be located on older pumps.
Unfortunately, it is common for parts of it to rust, as water accumulates at the bottom of the diesel fuel.
That's another reason why you should definitely drain the fuel filter every 15,000 km.
Rust can cause the threads to bind or even seize.
Is your fuel injection timing correct?
If not, then the valve can naturally reach its limit and display an error message.

What is the part number of this item, and what is the price?

In the workshop, they said that the start of injection is within the specified tolerances...