Golf Cabrio Performance Issues: Troubleshooting Guide

Hello!

"Since last summer (2006), I've been experiencing a performance issue with my 3.5-liter convertible (engine code AHU, 66 kW TDI). As soon as I drive at a slightly higher speed (usually on the highway, starting around 130 km/h), the engine control unit switches to limp mode – suddenly, there's no power. If I then turn off the engine (i.e., switch off the ignition) and restart it, everything works normally again. After a few meters or kilometers (depending on the speed), the problem reappears."

Following recommendations from some people, I had the error memory read out (privately), which revealed errors 00575 and 00528. I informed an employee at VW about these errors, who advised me to replace the solenoid valve, which I did. After that, the problem did not reappear for about 1 week, after which it was the same again.
Since the convertible was put away for the winter after that, I unfortunately couldn't continue investigating the problem.

Perhaps someone else has experienced similar problems and can offer advice.

THANK YOU and best regards.

CHRIS

Hello,

According to the error code, your desired boost pressure is not being reached.
Here are some possible reasons why the actual value is below the target value.
The solenoid valve is only one.
Another possible cause could be a dirty vacuum hose on the turbocharger, or a leak in the charge air system.

Please describe the problem in more detail. Does it only occur at high speeds, or does it also happen when you accelerate forcefully in lower gears?

Best regards, Jochen.

Jochen_145 wrote:

Please describe the problem in more detail. Does it only occur at high speeds, or does it also happen when you accelerate forcefully in lower gears?

Thank you very much for your reply!
"So, the problem only occurs when I'm driving on the highway, usually starting around 120 km/h; I haven't experienced any issues below that speed. For example, when I'm driving on a regular country road at 100 km/h, I never have this problem. It only happens at higher speeds."

The AHU is a wastegate turbocharger.
He has an overpressure valve.

A nice 003-008-011 log, and then we can say something.

"Error code 00528 is related to the altitude sensor; if it's malfunctioning, it may also be causing incorrect boost pressure regulation, as far as I know."

m;

dieselmartin wrote:

A nice 003-008-011 log, and then we can say something.

"Sorry, I'm a novice in this area - what does that mean?"

Hi.

When troubleshooting in a structured way, the first step is to determine what the engine is actually doing. Blocks 003, 008, and 011 are the most important ones that VAG-COM displays for performance analysis. These blocks show you the air mass, fuel injection quantity, and boost pressure.

Okay, connect VAG-COM to the laptop, plug the interface into the car, and head out onto the open road, floor it! You'll find plenty of help online by searching for "DZR" or "Durchzugs*".

Error 00575 is kind of like someone spitting in your face... You know something's not right, but whether they're drunk or have a stomach bug, you won't know for sure until you really investigate.

So, let's go get an EKG and blood work .

m;

dieselmartin wrote:

Hi When troubleshooting in a structured way, the first step is to determine what the engine is actually doing. Blocks 003, 008, and 011 are the most important ones that VAG-COM provides for performance assessment. These blocks show you the air mass, fuel injection quantity, and boost pressure. Okay, connect VAG-COM to the laptop, plug the interface into the car, get on the road, and floor it! When searching online, you'll find plenty of help related to "DZR" or "blow-off valve." Error 00575 is kind of like someone spitting in your face... You know something's not right, but whether they're drunk or have a stomach bug, you won't know for sure until you really investigate. So, let's go get an EKG and a blood test . m;

Okay THANK you for the information and explanation.
I'll let you know when I have more information!!

The AHU is a wastegate turbocharger.
He has an overpressure valve.


Yes and no.

In the Passat, the AHU engine used a wastegate turbocharger, while in my Audi, the AHU engine uses a variable geometry turbocharger (VTG).
In golf...? Well, I'll just believe you now, since you've probably seen more golf with AHU than I have.

So, check the overpressure sensor instead of the vacuum sensor.

Best regards, Jochen.

AHU with VTG... never .

Are you perhaps referring to the AHH, which is the longitudinal version of the ALH (90 hp VTG in the G4)?
The AHH was also available in the 3B model.

m;