Warning: Defective Konnwei KW-902 on the market

[Turbo3]

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.

 

[mwalsh]

Yikes!

Hope you posted this warning in a review on Amazon too?

 

[alozzy]

Thanks for the warning! I've got the same device and it seems to be fine but I'll definitely check the resistance.

Probably explains these threads too:

http://www.mynissanleaf.com/viewtopic.php?f=30&t=23721&p=490436&hilit=warning#p490436

http://www.mynissanleaf.com/viewtopic.php?f=30&t=23767&p=490771&hilit=bluetooth#p490771

 

[cwerdna]

Yowza!

Mods: If this isn't a sticky, can we make it one?

Also, if I don't get around to it, can someone add a warning to http://www.electricvehiclewiki.com/?title=Leaf_Spy_Pro&redirect=no#Clone_ELM327_Bluetooth_Scanner to AVOID this dongle for the time being?

Anyone who bought one that is causing some major abnormal behavior on the car should post a review on the site they bought it from (e.g. Amazon). If they find the resistance is out of whack, they should also post a review. Some folks may only look at reviews from verified purchases.

Turbo3: Do the pinouts at http://connector.pinoutguide.com/16_pin_car_J1962_OBD_2_special/ look right? (I quickly found this via Google.)

 

[Turbo3]

Yowza!

Mods: If this isn't a sticky, can we make it one?

Also, if I don't get around to it, can someone add a warning to http://www.electricvehiclewiki.com/?title=Leaf_Spy_Pro&redirect=no#Clone_ELM327_Bluetooth_Scanner to AVOID this dongle for the time being?

Anyone who bought one that is causing some major abnormal behavior on the car should post a review on the site they bought it from (e.g. Amazon). If they find the resistance is out of whack, they should also post a review. Some folks may only look at reviews from verified purchases.

Turbo3: Do the pinouts at http://connector.pinoutguide.com/16_pin_car_J1962_OBD_2_special/ look right? (I quickly found this via Google.)

The graphic is for the Leaf side. I have added a picture of the OBDII side showing where to measure to the first post.

 

[Turbo3]

Yikes!

Hope you posted this warning in a review on Amazon too?

Not only did I post a review but also sent a note to the seller. The seller contacted me by email early this morning asking for additional information so they are taking this very seriously.

This seller had no way of knowing about this problem (only one positive review) but has responded immediately when notified of it. In my reply I highly recommended they stop selling it until they notify the manufacturer and get a new shipment of defect free adapters.

Of course this has to happen on the adapter I have been recommending :-(

 

[sub3marathonman]

I'm wondering if there is any danger using a much older Konnwei KW-902. I got mine about 10/2015.

The strange thing is it worked fine for about a year. Then I started leaving it on all the time, because I worried about the On/Off switch going bad. It seemed like within a few months, it stopped working. So I waited a few more months, hoping it would work again. Then I ordered the OBDLink LX, which is supposed to be a high quality unit, at a much higher price. However, the higher price will be offset if it lasts a lot longer.

So, I got the new one, ready to plug it in, and decided, one last try for the Konnwei. And YES, it works again! :shock:

So for at least the time being I've left it plugged in, and on, until it goes out again.

But now I'm wondering, can even the older Konnwei adapter, or any adapter that fails, damage the OBDII network of the LEAF?

 

[chirpyboy]

Wow, I bought one off eBay recently and had this same problem (paired with phone but sent no valid data... eventual I-key error & T/M System Malfunction).
I returned it for a refund, and bought another off Amazon which works.

I wish I hadn't sent the bad one back already so I could check its resistance. The good one is 120ohm as expected.

ones I bought:
bad: http://www.ebay.com/itm/141978657396
ok: http://www.amazon.com/gp/product/B01LNJ77YI B01LNJ77YI

 

[cliff]

I thought the CANBUS was only terminated at the 2 ends?
Seems odd the diag port would also have a terminating resistor.
The 2012 service manual seems to show the VCM, and BCM as
the 2 units with active termination for the CAR-CANBUS.
I see my adapter also has the termination resistor in it.

Thinking about it, I guess during diags, it is considered better,
to reduce the reflection from the connecting wire, even though
the CANBUS load is increased.

 

[Turbo3]

I thought the CANBUS was only terminated at the 2 ends?
Seems odd the diag port would also have a terminating resistor.
The 2012 service manual seems to show the VCM, and BCM as
the 2 units with active termination for the CAR-CANBUS.
I see my adapter also has the termination resistor in it.

Thinking about it, I guess during diags, it is considered better,
to reduce the reflection from the connecting wire, even though
the CANBUS load is increased.

Every node on the CAN bus must have a 120 ohm resistor across the +/- CAN signals right next to the CAN transceiver pins. When you plug in the OBDII adapter you are adding another node which must have one across its CAN transceiver pins.

 

[Turbo3]

Would you be willing to open up your new one to see if it has the old or new circuit board inside?

The old one uses separate wires to the display panel.

The new one uses a single flat cable.

(I have no idea why my email address is appended to the end of the quote. I did not put it there.)

Wow, I bought one off eBay recently and had this same problem (paired with phone but sent no valid data... eventual I-key error & T/M System Malfunction).
I returned it for a refund, and bought another off Amazon which works.

I wish I hadn't sent the bad one back already so I could check its resistance. The good one is 120ohm as expected.

ones I bought:
bad: http://www.ebay.com/itm/141978657396
ok: http://www.amazon.com/gp/product/B01LNJ77YI B01LNJ77YI

 

[cliff]

The 2012 service manual shows that when the VCM is disconnected that
measured resistance on the CANBUS side is 120 ohms(seeing the BCM),
but when disconnecting the ABS unit the resistance seen on the CANBUS
side is 60 ohms(seeing both VCM, and BCM). This would agree with terminations only on the 2 ends.
There are 11 controllers on the car-can side, so if each has a 120 ohm
resistor, then the resistance seen would be 11 ohms. This is much less
that 20 ohms, so that adding a parallel 20 ohms would have a small effect
on load (but of course would add a reflection).

 

[Turbo3]

The 2012 service manual shows that when the VCM is disconnected that
measured resistance on the CANBUS side is 120 ohms(seeing the BCM),
but when disconnecting the ABS unit the resistance seen on the CANBUS
side is 60 ohms(seeing both VCM, and BCM). This would agree with terminations only on the 2 ends.
There are 11 controllers on the car-can side, so if each has a 120 ohm
resistor, then the resistance seen would be 11 ohms. This is much less
that 20 ohms, so that adding a parallel 20 ohms would have a small effect
on load (but of course would add a reflection).

Yes, you are correct. I should have said every ending node.

Almost all OBDII adapters have a 120 ohm resistor. Exceptions I have found are ones by GoPoint, PLX, Vgate and the Consult 3+ which have no resistor.

 

[chirpyboy]

Would you be willing to open up your new one to see if it has the old or new circuit board inside?

The old one uses separate wires to the display panel.

The new one uses a single flat cable.

Sure. Just checked and my new one has separate wires.

I had actually opened the bad one before returning it, because I heard something loose inside thinking that might be the problem (it was a tiny ball of solder). I remember it looked different and had a little flat ribbon cable.

(I have no idea why my email address is appended to the end of the quote. I did not put it there.)

This forum seems to do some hiding of Amazon links; somehow it sucked in your email? :?

 

[Turbo3]

So it might be that all new manufacture with the new circuit board and the flat cable have the 20 ohm resistor.

This is pointing to a basic manufacturing error in the use of 20 instead of 120 perhaps on the assembly instructions or a miss read of the documentation used to load up the parts.

 

[user 20964]

Bought this a few weeks ago based on LeafSpy recommendation, but it would never stay connected so I tried another brand BATX. I just checked and it has the 20ohm resistor and I opened it up and it has the flat ribbon cable. Returning today to Amazon as defective.

 

[Snlj]

Confirmed! The replacement Konnwei KW902 scanner I purchased to replace my previous, malfunctioning unit only shows 20 ohms across the two pins you highlighted in your picture. Thank you for finding this out! I'll get this returned immediately.

 

[AdamFist]

This thread was helpful and timely since I received my Konnwei KW902 yesterday. I'm returning it to Amazon. In the meantime, does anyone have a recommendation for an alternative ODB2 scanner that works?

Thanks,
Adam

 

[Turbo3]

This thread was helpful and timely since I received my Konnwei KW902 yesterday. I'm returning it to Amazon. In the meantime, does anyone have a recommendation for an alternative ODB2 scanner that works?

Thanks,
Adam

The currently available test version of LeafSpy Pro supports the newer Bluetooth 4.x LE as will the next official releases of all versions of LeafSpy which I hope to start rolling out within the week.

There are two supported Bluetooth 4.x LE OBDII adapters. The LELink and the PLX Kiwi 3 with the LELink from Amazon being the cheaper of the two. The LELink is what I use and works with the iOS version of LeafSpy and will work with the next release of the Android versions of LeafSpy.

Bluetooth 4.x LE being a low power adapter will result in less drain from your 12v battery when the Leaf is off. There is also no pairing required.

Anyone with the Android version of LeafSpy Pro can try the latest test version using this link.
https://play.google.com/apps/testing/com.Turbo3.Leaf_Spy_Pro

 

[Turbo3]

This thread was helpful and timely since I received my Konnwei KW902 yesterday. I'm returning it to Amazon. In the meantime, does anyone have a recommendation for an alternative ODB2 scanner that works?

Thanks,
Adam

I forgot to ask. Are you returning because it measured 20 ohms or just because it is a Konnwei KW902?

If you don't have an ohm meter you can tell if it is new manufacture by opening it up and seeing if it has a flat cable to the top display board. If it is new production it is probably bad. Measuring 20 ohms is of course the gold standard for defective.