Intermittent Fuel Vent Issues: Troubleshooting Guide

Hi,
I have a Golf 4 (model year 2003) – the warranty just expired. For a few weeks now, the display has been showing "Exhaust - Workshop." A diagnostic scan of the engine control unit shows an intermittent fault code related to the fuel tank ventilation system.
After the error is reset, there is usually a period of 3-4 weeks of stability, after which the error reappears.
The workshop keeps resetting the error.
Does anyone have any ideas?

Best regards,
fred

Hi,

Okay, I've just read the error codes.

VAG-COM Version: DRV 311.3-S

Control unit part number: 036 906 034 DR.
Component or version: MARELLI 4MV 4464
Software Coding: 0000031
Workshop Code: WSC 01391
Sure, here is the translation of the text from German to English:

"1 error found:"
16825 - Tank ventilation system: Flow rate error.
P0441 - 000 - -
After resetting the error, the warning light is off, and the display shows "Exhaust - Workshop".
"It's also gone. However, if I drive a few kilometers, the same error code reappears in the error memory, but the warning light and the display indicator remain off?"
The error is only stored in the error memory.

Best regards,
fred999

Well, in that case, I would also assume there's an error that exists.

Okay, here's a random guess, but it's a fairly common issue: The AKF valve is stuck/broken.

The error memory entry is set when the error occurs for the first time. If the error does not reappear, it is set sporadically. If the error is detected again during subsequent tests, and the entry is already in the memory, a counter is incremented. Depending on the design, the control system may also trigger an alert after the 3rd or 5th occurrence of the same error within a specific test period.


Furthermore, it could be a software error within the control unit.
Please take your car to the dealer and have them use the latest flash CD to check if there's a new software version available for the car. There definitely is a newer version, but I'm not sure if it's the one you already have installed.

For your information, this is a BCB engine (1.6L 16V).

You're welcome, vagtuning.

I replaced the AKF valve, and the error is gone.

Thank you again for the helpful and informative response.

Regards,
Fred999

Glad it helped!

As a reference for the future...

http://wiki.ross-tech.com/index.php/16825/P0441/001089