If you’re working on a 2021 VW Jetta (Mexico) with all keys lost and your Keydiy KD-X4 or Yanhua ACDP2 gets stuck showing a “1-1” code, don’t panic. This simple fix has worked for multiple users.
What Happens?
You follow the normal AKL (All Keys Lost) procedure using a dealer pre-coded key. The tool detects the key and enters learning mode, but the vehicle simply won’t start. The screen shows a frozen “1-1” indicator – a clear sign the ECU is stuck.
You’ve already tried:
- Using a power booster
- Checking for SFD (none present)
Nothing works.
The Solution (No Special Tools Required)
This fix requires nothing more than a basic wrench and 10 minutes of patience.
Step 1: Open the vehicle bonnet
Step 2: Locate the battery and disconnect the negative (-) terminal
Step 3: Wait for 10 full minutes – this allows the ECU to fully reset
Step 4: Reconnect the negative terminal
Step 5: Perform the key programming sequence exactly as you did before
Does It Work?
Yes. Here’s what one user reported after trying this fix:
“Update: FIXED AFTER DISCONNECTING BATTERY FOR 10 mins negative then programming key. Disconnected negative for 10 mins, reconnected, the learned now it is good!”
Why This Works
Disconnecting the battery for an extended period drains residual capacitance in the vehicle’s modules, forcing a full reset of the ECU and immobilizer system. This clears the stuck “1-1” learning state and allows the key programming to complete successfully.
Tech support:
Email: sales@OBDexpress.co.uk
WhatsApp：+44 7418609676
WeChat: 15705931767
Working Time: 9:00am – 18:00 pm (UTC+08:00), Monday to Friday.
