If your Xhorse VVDI Key Tool Max pro fails to start communication with vehicle and asks to check if the OBD wiring is normal, follow guide below to do a device self test.
VVDI Key Tool Max Pro Self Test
In main menu select IMMO Programming
Select More Functions
Press Device Test
Select K-line Test
Short Connect PIN7 and PIN15 with the OBD connector.
Then also do CAN line test.
If Key Tool Max Pro says the test failed, there is something wrong with the device. You may need to send it back for repair.
If your VVDI Mini OBD Tool has a communication error, you can do the same. Go to more functions-device test. Do both K-line and CAN Line test.
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