help of "channels disappear when ignition ON" on MQB Passat B8

Dears,,,

I'm a newbie and first allow me to say hello to everybody here, and I got a problem which I hope someone here can help with...

I read the thread posted in the forum which presented a way to complete the tweak "Passat B8 ambient lights to 10 colors from factory-enable 3 colors". I believed that was my thing.

However, odd thing came up when I was trying this tweak on my car, which was, some channels were only to be seen the moment I powered off the car, and it would never appear when I left the ignition ON. below are my steps:

1, cable gets connected, where I forgot to power up. I open VCDS and see "IDE09732-ENG133384-Interior light: light configuration-Ambient_Farbliste_HMI" not active, I change it to active.
2, I update "Ambient light color list" as per my RGB table.
3, car powered up and rebooting the Nav system by pressing and holding the knob of the control.
4, it turns out the ambient lights on the doors are off and the menu to select color in "settings - background lights" disappear.
5, with ignition ON, I open VCDS again, the channels I worked on just vanish...
6, I open the 09 module immediately I power off the vehicle, the channel show up again.
7, Update "IDE09732-ENG133384-Interior light: light configuration-Ambient_Farbliste_HMI" to active.
8, powering up, the light strips come back...

End of the story, I got 2 questions...
1, Can someone help with this "appear and disappear" thing...
2, Can someone share the steps and codes for tweaking ambient lights to 10 colors on a MQB Passat B8...

finally, below a part of Auto-Scan:

Please post a complete Auto-Scan.

-Uwe-

Thanks for your reply. Will do and upload.

Thanks again!

Auto-Scan:


09 module adpmap with ignition ON, I couldn't extract a adpmap when the car was powered off.

radiocheck said:

1, Can someone help with this "appear and disappear" thing...

Click to expand...

I have seen some ignition on/off and disconnect flows like yours cause similar trouble. When you open the module in this state, do you see a 'No ROD data found' or similar pop-up bubble? Something like this was pseudo-repeatable on my 2018 Atlas when I was playing around a couple months ago, recoding stuff in 17-Instruments. I thought for sure I broke my instrument cluster the first time I saw it, but I got around it, and then saw it again several times when playing with other 17 codings.

IIRC, the workflow was me connected to 17 with the engine running, browsing the coding table looking for nifty stuff. I'd find something, tee it up, and then shut off the ignition so I could apply the coding. Again IIRC, the existing VCDS session would stay up through the ignition-off event, until I executed the recode, then I'd get dumped out of the session as the coding change made the cluster restart, and 17 wouldn't let VCDS reconnect after restart with ignition off, since that's sleepy-time. Then I'd go ignition-on and reconnect, and VCDS would often show me a 'No ROD data found' error, and that means you're going nowhere much on a UDS module. I feel like I tripped this once somewhere other than 17 too, but I'm not sure.

When this happened, I saw some neato stuff like 'No ROD data found' on direct connect to 17, but then ROD data would be found perfectly fine in an Auto-Scan. Repeatedly on same run of VCDS. One time, it managed to get stuck in that state through a PC reboot, it turned out I had to power off/on the physical HEX-NET interface. I theorize VCDS/HEX-NET was trying and failing to re-fetch the VIN and chassis type during this workflow, which is critical to looking up the right UDS/ROD data, and somehow either forgot or was unable to retry.

Your workflow involves a lot of ignition on/off and also a nav unit reboot while you're messing with it, so that made me remember it.

Normally if I trip over something interesting and repeatable, I try to collect a debug and pass it along, but in this particular case I was way more interested in playing with certain newfound gadgets and subsequently forgot about it. The Atlas is due for an oil change this weekend, if I remember, I'll see if I can trigger this again.

radiocheck said:

09 module adpmap with ignition ON, I couldn't extract a adpmap when the car was powered off.

Click to expand...

Over-generalizing slightly here, but as a rule, almost nothing in the car will be listening to open a new diagnostic session with the ignition off. Some modules will be willing to keep an existing session open when you shut off the ignition, for a while, but you won't get back in after a disconnect.

Always do your VCDS work with the ignition on. Engine running is optional, depending on what you're doing. For engine troubleshooting you'll obviously need the engine running. For many modules, certain coding and adaptation work will fail if the engine is running.

thanks so much bro.
I didn't see 'no rod data found' or other error when it happened.
I had to stay in select menu to click on 09 immediately the car went ignition OFF. otherwise I would miss the window.
I tried like 10 times with ignition ON to find those chhannels but none...
Agreed with you that session closed and would never open again in the state the ignition OFF.