Customer Issue:
When using the Xhorse VVDI Key Tool Plus to add a 2023 VW MQB49 5C key, the device failed to read the original key data. The system repeatedly displayed the error message:
“CLK line not connected.”
All wiring and soldering were checked and confirmed correct. The same error occurred even when using a 5C/5D solder-free adapter, leading to confusion about the root cause.
Root Cause Analysis
This issue is not caused by software or tool failure. In most cases, it is related to an unstable or incomplete CLK signal connection on the key chip.
Solution Steps
1. Verify Wire Connections
Do not rely solely on wire colors.
Carefully match each wire according to the label markings, ensuring they correspond to the correct chip pins.
2. Check the CLK Line
The CLK signal is critical for MQB49 key data reading.
- The CLK line corresponds to Pin 24 of the chip
Even a slight misalignment or weak contact on this pin can trigger the error.
3. Inspect the Chip Pins
- Use a microscope to closely examine the chip pins
- Look for cracked, lifted, or oxidized pins
- If damage is found, gently polish or repair the pin to restore conductivity
4. Secure the CLK Connection
- Re-solder the CLK wire firmly if using traditional wiring, or
- If using a 5C/5D solder-free adapter, press a fine needle or probe firmly onto the CLK pin during the reading process to maintain stable contact
Result
Once the CLK line connection is stable and secure, the Xhorse Key Tool Plus will successfully read the original MQB49 5C key data, allowing key programming to proceed normally.
✅ No tool replacement required
✅ No software update needed
✅ Hardware connection issue resolved
Skype: xhorsevvdi.com
Whatsapp: https://wa.me/8613983756354
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