FAQ
TL;DR: Fix the Yatour memory issue by feeding constant +12V to pin 16 and adding two rectifier diodes (1A); “1A is enough.” [Elektroda, Gumis_sx, post #16694798]
Why it matters: This prevents resets, stops unintended backlighting, and avoids battery drain while keeping last-track memory. The FAQ is for Audi A4 B6 owners using Yatour/USB CD-changer emulators who ask “how do I fix last song not remembered?”
Quick Facts
- Pin 16 on the changer line needs constant +12V for the emulator to remember position. [Elektroda, DriverMSG, post #16688605]
- Permanent +12V is available at the bottom ISO plug, pin 4, on the Audi Chorus loom. [Elektroda, DriverMSG, post #16688803]
- Use two rectifier diodes, approx. 1A each, to isolate radio and emulator power. [Elektroda, Gumis_sx, post #16694798]
- Bridging without isolation can light the headlight switch backlight continuously. [Elektroda, Gumis_sx, post #16688822]
- After diode isolation, the changer retains tracks and stations without unintended backlighting. [Elektroda, Gumis_sx, post #16694798]
Why doesn’t my Yatour remember the last played song in an Audi A4 B6?
The emulator loses memory because pin 16 (changer supply) doesn’t have constant +12V when the ignition is off. Provide a permanent feed. Use diode isolation so power does not backfeed other circuits. After isolating and feeding constant +12V, the changer resumes tracks correctly. [Elektroda, DriverMSG, post #16688605]
Which wire gives constant power on the Audi Chorus radio?
Use the bottom ISO plug, pin 4, which carries permanent +12V. Route this to the changer’s pin 16 to supply memory power. Add diodes to prevent backfeeding. This delivers continuous power while keeping the rest of the loom stable. [Elektroda, DriverMSG, post #16688803]
How do I wire the fix safely so I don’t drain the battery?
Isolate the new constant feed with rectifier diodes. Insert two diodes as shown by the poster’s solution to block reverse current into the radio lighting and other circuits. This preserves memory but stops parasitic loads when the car is parked. [Elektroda, Gumis_sx, post #16694798]
I bridged power and now the light switch backlight stays on—why?
A direct bridge lets current backfeed from the constant line into the radio harness and lighting circuit. The fix is diode isolation. Once diodes are added, the backlight no longer stays illuminated with ignition off. [Elektroda, Gumis_sx, post #16688822]
What diodes should I use and how many?
Use two rectifier diodes rated about 1A. Install them according to the provided diagram so current flows toward the emulator but cannot return toward the radio. As the poster wrote, “1A is enough.” [Elektroda, Gumis_sx, post #16694798]
Can I just leave the radio powered without ignition?
You can, but it risks draining the battery if you forget to turn it off. As one expert warned, the radio will draw current like you left it on overnight. Safer is diode-isolated constant power only to the memory line. [Elektroda, DriverMSG, post #16688779]
What voltage should I see during testing?
You’ll see about 12.5V only with ignition if the feed isn’t constant. That confirms the problem. After the fix, pin 16 should have +12V with ignition off as well. Use a meter while the radio is connected. [Elektroda, Gumis_sx, post #16688679]
Step-by-step: how do I make the Yatour remember the last track?
- Cut the original wire going to pin 16 (changer supply).
- Run a new feed from ISO bottom plug pin 4 (constant +12V) to pin 16.
- Insert two 1A rectifier diodes per the diagram to block backfeed.
After this, memory and lighting behavior are correct. [Elektroda, Gumis_sx, post #16694798]
Will this fix also keep my FM presets and earlier settings?
Yes. With constant +12V to the correct pin and proper isolation, both the changer memory and radio stations persist. The poster confirmed stations and tracks were retained after the modification. [Elektroda, Gumis_sx, post #16694798]
Do I need special tools or just a multimeter?
A multimeter is enough for diagnosis. You’ll also need crimp connectors or solder, heat-shrink, and two 1A diodes for isolation. Verify voltage with ignition off before finalizing. This ensures pin 16 gets true permanent +12V. [Elektroda, DriverMSG, post #16688605]
What if pin 16 shows no power with ignition off?
Disconnect the original ignition-switched feed to pin 16. Then supply it from the constant +12V at ISO pin 4 through diodes. This restores memory without powering the entire radio continuously. [Elektroda, DriverMSG, post #16688757]
Why did bridging fix memory but break other behavior?
A raw bridge feeds constant power to multiple circuits, not just the emulator. That fixed memory but energized the lighting path, causing the backlight to glow. Diode isolation fixes both issues together. [Elektroda, Gumis_sx, post #16688822]
Is the 1A diode rating really sufficient long-term?
Yes. The solution report used two 1A rectifier diodes and confirmed stable operation. The memory line current is low, and the diodes act as one-way gates to protect the harness. [Elektroda, Gumis_sx, post #16694798]
What’s the quick expert takeaway before I start?
“Disconnect this cable from the radio and connect it directly to 12V,” then isolate with diodes. That sequence fixes memory and prevents backfeeding. Measure first, cut second. [Elektroda, DriverMSG, post #16688757]
