VW T4 Error Codes: Troubleshooting Guide

Hello everyone,

At the beginning of my time on this forum and in your community, I have a question about error codes. The newly acquired vehicle:

VW T4, manufactured in November 2002.
2.5L, 88 HP, AJT engine.

Out of curiosity, I read the error memory, and the result was:

Control Module Part Number: 074 906 018 AK
Component and/or Version: 2.5L R5 EDC 0000SG 3905
Software Coding: 00002

3 Faults Found:
18058 - Powertrain Data Bus: Missing message from instrument cluster.
P1650 - 35-10 - - - Intermittent
18039 - Accelerator Position Sensor (G79): Signal too high.
P1631 - 35-00 - -
18040 - Accelerator Position Sensor (G79): Power Supply Malfunction.
P1632 - 35-00 - -

I was able to clear the accelerator pedal error for now, let's see if it reappears. What I can't clear, logically, is the instrument cluster error. The bus apparently received two new keys just before being sold to me, and the WFS module is listed in the VW workshop history. What does this error indicate? Was it tampered with, is something not properly configured, is the WFS active? Does the engine control unit (MSG) need a connection to the WFS?

Thank you in advance for your hopefully insightful answers.

Best regards,

Bucky.

Hello,

The message from the data bus might not mean anything. Just clear the error and see if it reappears. It's possible that a new speedometer is installed that isn't sending the correct information, but that's not necessarily the case.

Best regards, Rainer.

Unfortunately, the error cannot be deleted. As I mentioned, work was done on the speedometer, and I believe the history (which I haven't read myself) indicates that the WFS module was replaced. Since this module is located in the instrument cluster, and the instrument cluster looks relatively new, it's quite possible that it is new. It's also possible that the mileage was slightly adjusted.

The last output test (Engine Overheat... something) is not working. Is this acceptable, or should a warning sound/temperature alert be displayed? The overheat LED works during the display test.

But the connection between the control unit and the AI isn't necessarily required, right? Then I'll just leave it as it is – never touch a running system...

Bucky2k wrote:

that the WFS module has been replaced. Since this is located in the KI

.
That's not correct. The WFS (Wheel Speed Sensor) was not actually integrated into the speedometer unit in the T4 until the very end. The WFS in the T4 is located in its own control unit, which is behind the speedometer.

Ah, thanks for the info. I just assumed it would be similar to most other VAG models.

Should I just ignore the error message? Or should I take out the KI (likely referring to a component) and check if everything is properly connected?

Please check the CAN bus distribution block to ensure everything is properly connected and that there is no corrosion, see T4-Wiki.de --> "CAN-Bus" or http://213.239.212.66/wiki/Can.