Graphics Card Issues: Troubleshooting Guide

Hello,

I installed a new GRA (Gas Return Assist) system with a new lever in my Volkswagen Golf IV, but it's not working exactly as expected.

Generally, I can activate the cruise control using the SET/ - button to have it maintain a certain speed. When I press the + (Res) button, it will also accelerate, but not in increments of 1.5 or 3 km/h, rather continuously (until I press the - button again).

Both brake switches and the clutch switch are okay according to the log.
If I look at group 6, field 3, then at least the assignment of switches to bits is correct.
OFF 000000
ON 000011, but sometimes also 001011.
Hold down the ON and SET buttons simultaneously: 000111.
Pressing the "ON" and "+/RES" buttons once results in "001011". This value remains until either the brake is applied or the "-" button is pressed, although pressing "-" only reduces the speed by 1.5 km/h.

The problem lies with the function of "+". While bit 3 can be clearly activated using "+", it's unclear how long the value needs to remain there. It seems possible that the value is only supposed to stay there as long as the button is pressed. However, since the value remains, the car accelerates continuously instead of just becoming 1.5 or 3 km/h faster.

I consider a wiring error unlikely, as the correct bits are essentially being transmitted.

Since I've read about faulty switches in several previous posts, I now suspect the switch itself (it might not be returning to its original position properly). Before I take everything apart again, I wanted to get your opinions on this.

Hi.

"Why don't you measure the switch with a simple multimeter? You should immediately hear the continuity beeper if there's a problem."

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hi Holger,

If the bit remains stuck in the control unit when you tap it, there is a high probability that the switch inside the lever is faulty.
Unfortunately, my original GRA lever also had a rather short lifespan... it seems to be mechanically quite cheaply made.

Best regards, Rainer.

Thank you for the answers.

The multimeter test revealed that the "+"/"RES" button does not release after being pressed – it remains engaged until the "-"/"SET" button is pressed.

Now I know why the switches were on special offer at VW - probably a batch with defects .

You can also check this with a built-in switch (at least in the Golf IV) by simply opening the upper steering column cover. However, it's helpful to use a cable with a 10-pin connector (e.g., an old computer cable) to extend the connection.


Here's the configuration I tested:
(therefore, disconnect the power supply connection for SW/BL (T10s/6)).
blue (T10s/2): "+" / "RES"
red/yellow (T10s/3): "-" / "SET"
white (T10s/5): "ON + ACTIVE" (i.e., opens when switched from the ON position to the OFF position).
sw/gn (T10s/4) (T10s/7): "ON"
bl/sw (T10s/6): Power supply, Class 15.

Okay, please provide the German text you would like me to translate into English.

and successfully diagnosed remotely again .

Then, Volkswagen would have to completely replace it and put a new one on the table, which you would then have to "install" by pressing buttons repeatedly and checking the shifting behavior with a multimeter.

Effort:
low cost... a real pain... lots of time.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.