Emergency Mode: Troubleshooting & Solutions

Hello, fellow diesel enthusiasts,
I've been having a problem since today.
I was driving comfortably along the B13 road and entered a town when the engine suddenly went into emergency mode.
He then turned off the engine and restarted it. The engine runs smoothly and evenly at idle speed, and the instruments indicate "everything is okay."
The moment I press the accelerator, the engine goes into limp mode and it doesn't respond to the throttle!
If I start the engine again, it runs normally. If I accelerate very gently and extremely slowly, the engine will rev up to its maximum speed. However, if I accelerate normally, the engine immediately goes into limp mode again.

Vehicle data:
Audi A6, model year 1999, engine code AKN, mileage 130,000 km. Timing belt kit and camshaft kit newly replaced.
Unfortunately, I don't have a diagnostic tool.
Please provide your diagnosis and advice!

Thank you very much.
Best regards, Bastianna.

Quote:

Unfortunately, I don't have a diagnostic tool.

"Sorry, the crystal ball isn't working very well right now..."

However, problems with the VP44 pump, as often happens, are possible.

hi Diesel mechanics,
I just spoke with a VAG master mechanic, and he suggested that it could be the turbo.
Can you briefly explain why it might be the pump?
Sure, no problem.
Best regards, Bastianna.

...because it's a VP44.

I would definitely rule out the turbocharger for now; everything else seems suspicious.

Unfortunately, my crystal ball seems to be on standby as well.

"Don't be so hasty, Matthias!"

Specifically, the early AKN engines have a design flaw that is often not recognized. The oil that lubricates the turbocharger flows under pressure to the shaft and leaves the turbocharger at the oil outlet, which is located relative to the oil inlet, without any pressure. It then flows back to the oil pan with the help of gravity.

However, if the back pressure in the crank mechanism exceeds 5 mbar, this no longer occurs, or only occurs intermittently. The oil stagnates in the charger, carbonizes, and also severely clogs the VTG (variable geometry turbine).

The most common cause is a malfunctioning or clogged crankcase ventilation system that can no longer effectively remove blow-by gases. These gases then enter the crankshaft system, leading to the problem described. Worn pistons can also be a cause of high pressure in the crankshaft system.

The described symptoms are a good match for a faulty VP44 pump; a broken driver module presents differently. If the driver module is defective, you won't be able to reach the maximum speed, as the motor won't run at all. It will simply shut off and won't restart.

If the VTG (Variable Turbine Geometry) is stuck, the engine management system might still be able to regulate the boost pressure increase when accelerating gently. However, during a kickdown, this is no longer possible because the lever force of the pressure sensor is too strong. The large change in lever position that is actually required over the short time (e.g., 8mm in 2 seconds) during acceleration is no longer achievable due to the fouling of the VTG.

"When idling, if I give it gas, does it go into limp mode due to a turbo defect? You never stop learning; I never would have thought that any emergency mode condition would be triggered with such minimal boost pressure. But if that's the case, then forget what I said, and I'll withdraw from the 6-cylinder discussion!"

First of all, thank you for your contributions.

It would be great if the pump could be turned off. I don't quite understand how, but Matthias also mentioned that the slight pressure buildup is enough to put the motor into emergency mode.
I'd like to try again to describe exactly what's happening.

Once the engine is started, it runs smoothly and cleanly, with a consistent idle.
As soon as I press the accelerator pedal, for example, to start driving (which is a completely normal situation), the engine goes into limp mode. The engine's RPM doesn't exceed 50, making it difficult for me to understand how the turbocharger could be overboosting.
Okay, gib mir den deutschen Text, den du übersetzt haben möchtest.
The AKN engine in the A6 is quite sluggish above around 2000 rpm, and there's almost no response below 1500 rpm. If a small hill appears and I don't want to stall, I have to downshift because otherwise the engine speed drops too low!

Deus Violentia, I would like to ask you to help me out with something.

Just to let you know, I experienced what I believe was a sudden and brief surge in power while accelerating yesterday, around 3500 RPM.
Could it be that the VTG (Variable Transmission Gear) malfunctioned and it wasn't actually an overspeeding situation?

@Matthias: I misread what the poster wrote about the engine, and my conclusion was definitely wrong. I thought he was saying the engine was producing more power under load, but upon closer reading, he was actually talking about the idle behavior. Sorry about that!

Therefore, my explanation might seem somewhat implausible, because you are partially right that the almost non-existent boost pressure means the VTG (Variable Turbine Geometry) doesn't adjust as much as described in idle. However, I still believe that the problem is related to a stuck VTG.

Questions/Advice for bastianna:

1. Go to a VW/Audi/Seat/Skoda dealership and have the error codes from the engine control unit read and printed out, otherwise we might be completely guessing here.

2. Does the engine somehow reach its rated speed?

3. Did the error appear gradually or suddenly, i.e., is this the "first time" it happened to you?

4. Can you check the access to the stage or pit, and verify the ease of operation of the VTG adjustment?
For example, you can connect a large syringe with a hose to the vacuum sensor, or manually move the component.

5. Check intake passages, inspect air filter, check mass airflow sensor.

6. Oil level above/at the maximum? (this is no joke!) --> Too much oil mist can damage the mass airflow sensor (MAF).

7. Check the VTG magnetic valve!!!

...that's a relief.

Regarding point 2, he wrote that this is achieved in the first post .

Deus Violentia wrote:

Questions/Advice to bastianna: 1. Go to a VW/Audi/Seat/Skoda dealership and have the error codes from the engine control unit read and printed out, otherwise we might be completely guessing here. Driving is really bad; I'm borrowing a proofreading device tomorrow. 2. Does the engine somehow reach its rated speed? Yes, but only with very gentle acceleration. 3. Did the error appear gradually or suddenly, i.e., is this the "first time" it happened to you? From one second to the next, for the first time. 4. Can you access a stage or pit, and can you comment on the ease of operation of the VTG adjustment? check? The VTG (Variable Turbine Geometry) is located above my engine, between the cylinder heads. The Memprand sensor pulls the linkage slightly upwards and without pressure, and then the linkage returns to its original position. For example, you can connect a large syringe with a hose to the vacuum sensor, or manually move the component. 5. Check intake passages, inspect air filter, check mass airflow sensor. I recently replaced the camshafts and also inspected the air passages; there are deposits present. The air filter and mass airflow sensor are new. After replacing the mass airflow sensor, I had Audi perform a test drive, and the technician said that the VTG (due to the boost pressure) is working correctly. 6. Oil level above/at the maximum? (this is no joke!) --> Too much oil mist can damage the mass airflow sensor (MAF). Of course, I also changed the oil filter, fuel filter, and engine oil, and the oil level is correct. 7. Check the VTG magnetic valve!!!

I haven't done that yet, but I will check it.

Here's one more note:

While researching a solution to my problem in the forum, I came across the following.

Engine entering emergency mode.
Cause: Moisture.
In this case, the windshield was replaced, and water entered the vehicle's interior, causing the brake and clutch switches to become wet.

"My windshield was also replaced, and it was raining on the day the damage occurred. However, I don't have any water inside the vehicle, but there is water in the area of the engine control unit."

I read the error codes on Sunday.
Error 00777: Sensor for accelerator pedal position, G-79.
I didn't do anything to the vehicle. After running the diagnostic scan, I started the engine and it ran normally again!
Regarding the water, I couldn't detect any water inside.
However, I still feel that it might be due to the humidity.
Do you have any further comments?

Best regards, Bastianna.

Sure, here's the translation:

"Again, please."
It has been raining here since Sunday evening. I just tried to drive again (Monday, November 22nd, 3:20 PM), and now it's going into emergency mode again.
Error code 00777: Throttle position sensor (G-79).
How can I proceed?

Please participate.
Thank you.
Best regards, Bastianna.

It seems the electronic throttle pedal is defective, which is likely causing the unusual driving behavior. Check the wiring, inspect the connector connections in the water tank near the control unit, and if everything appears to be okay, install a new throttle pedal.

bastianna wrote:

Hello, diesel enthusiasts, I've been having a problem since today. I was driving comfortably along the B13 road and entered a town when the engine suddenly went into emergency mode. He then turned off the engine and restarted it. The engine runs smoothly and evenly at idle speed, and the instruments indicate "everything is okay." The moment I press the accelerator, the engine goes into limp mode and it doesn't respond to the throttle! If I start the engine again, it runs normally. If I accelerate very gently and extremely slowly, the engine will rev up to its maximum speed. However, if I accelerate normally, the engine immediately goes into limp mode again. Vehicle data: Audi A6, model year 1999, engine code AKN, mileage 130,000 km. Timing belt kit and camshaft kit newly replaced. Unfortunately, I don't have a diagnostic tool. Please provide your diagnosis and advice! Thank you very much. Hi bastianna

.

Hi everyone,
I found the cause.
The plastic box that houses the engine control unit is attached to the body with 2 screws, and they were a bit loose. I tightened them, and now it's working again.
So, it turns out that moisture was actually the cause of the problem!

I would like to express my sincere gratitude once again for your helpful contributions.

Have a nice weekend and greetings.
bastianna

Hello Bastianna,

'I once had the same issue. At the time, I had only installed the cruise control system, and a tiny amount of moisture in the area of the MSG/throttle pedal connectors seems to have been enough to trigger the 777 error. The entire system seems to be designed with a very high impedance, making it sensitive to interference currents. Therefore, my suggestion is to dry the area around the MSG/inside the MSG box/connector contacts with a hairdryer or hot air gun, possibly disconnecting the connectors beforehand. Otherwise, the error may reappear from time to time.'

VG
winschrott