Communicating With The Computers

Golf GTi Mk3 Restoration, May-2017

The Golf Mk3 has an OBDII interface for communicating with its on-board computers/controllers and uses a proprietary VAG protocol that needs a dedicated code reader such as the VGate VS450 device. This allowed me to get information including fault codes from the ECU and ABS controllers:

Info from the ECU and ABS controllers and read any fault codes.

Using this device, I could reset the faults on the ECU but not the ABS. Every attempt to reset ABS faults returned a “Reset Failed” error.

I then tried VCDS Lite (release 1.2) to try resetting the ABS codes, but unfortunately encountered the “Too many errors” fault that prevented any communication with the ABS controller. This appears to be a common error and there are many solutions available on the ‘net but none of them worked for me.

I tried playing around with the port settings on the Windows 10 laptop that I was using and eventually found a configuration that worked. In Device Manager / Ports / Advanced Settings, the port was set up as below:

The values set for Latency, Minimum Read & Write Timeouts were arrived at using more luck than judgement. Working on the assumption that the ABS controller (being 20+ years old) would have a slower interface than the Laptop, I increased the timeouts to allow more time between each byte transmitted & received. The latency is the time it takes for the Laptop to respond to a transfer – I reduced this to ensure the ABS controller was never waiting for the Laptop.

With these settings, the ABS controller function on VCDS Lite worked perfectly and allowed me to do everything I wanted with the ABS, particularly reset any residual error codes:

So, with all the residual historic fault codes cleared, I was able to confirm that the ECU & ABS were working properly.