DO NOT PLUG A NEWLY BOUGHT KONNWEI KW-902 UNTIL YOU READ THIS.
I have recently been getting reports of strange things happening (I-Key error) when newly bought Konnwei KW-902 adapters are plugged into the Leaf.
I bought one this week and got it today from Amazon and had the same problem.
On opening it up I noticed they have changed the circuit board from the board in the old one I have been using.
The problem is that on at least some they have used the wrong resistor across the CAN bus. The spec is 120 ohms
across pins 6 and 14.
They are using a 20 ohm
resistor which is a near short of the CAN bus. If they are using automated equipment to build their boards then they most likely loaded the wrong reel of resistors. That means there are potentially many many of these out there.
Before plugging in a newly bought Konnwei KW-902 into your Leaf please have the resistance between pins 6 and 14 measured. If it is not 120 ohms
return for a replacement until you get one with the correct resistor in it.
Shorting out the CAN bus is very serious. If you experience any strange behavior when using any OBDII adapter immediately stop using it and have the resistance checked. Never drive your Leaf under these conditions.
The CAN bus is used to control the vehicle it is not just a monitoring port. The communications on the CAN bus control the Leaf and shorting it out should never be allowed.
I have had one other user confirm 20 ohms
on his defective Konnwei. Please send me a note if you also measure 20 ohms
Two more confirmed to have 20 ohm
resistors from AliExpress.
These are the two pins to check for 120 ohms.
Here is what it looks like inside courtesy of a excellent picture from Mark Stevens. I have marked the bad resistor in RED
. Removing this resistor will fix the problem.