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Sun Oct 08, 2017 12:48 pm

I am happy HAPPY HAPPY!!! to report that my car now charges successfully at all charging stations. Background: there are several threads on this forum about Level-2 charging failing at certain stations but not others; the fix is to replace a diode and not to have Nissan charge you $2800 to replace the entire charging module.

I realize this is yet another thread on the same topic, but I thought I'd share some info about the fix and hopefully make it easier on other people. I used these steps as a starting point: ... /i-rcsHp8p

Here's my take on these steps, slide by slide. I've added BOLD to the actual steps where you do something. The whole process is five steps, really.
  1. I bought 25 of these diodes at Amazon for $6.00. Seemed like the easiest way to get the right thing.
  2. This image means nothing for repairing your Leaf. Skip it.
  3. So you know what's broken.
  4. This step is easy enough. A flat-head screwdriver helps. Or strong fingernails.
  5. This was the hardest part for me. (Still not that hard.) I had trouble finding the little clip on the bottom to press so I could pull it out.
  6. Nothing to do here.
  7. Removing the overflow tank was completely unnecessary for me...
  8. ... because I had no need to release this connector.
  9. This step is also unnecessary.
  10. Just unscrew these four screws to get to the wire. Since I hadn't removed the connector, mine didn't come this far out. Not an issue; you don't need to pull it out this far just to do the soldering.
  11. Find the right wire.
  12. That's the one.
  13. Put that diode where it belongs
That's it! Step 1 is buy the thing, step 4 is remove the cover, step 5 is disconnecting the orange connector, step 10 is unscrewing so you can pull out the unit to get to the wire. Step 13 is adding the diode.

And voila, it works. (Step 14, put it all back together.)

Thank you all for your help. So glad to have this issue behind me without costing three grand to do it.
Last edited by tn77 on Tue Oct 10, 2017 8:18 am, edited 1 time in total.

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Sun Oct 08, 2017 1:37 pm

Congrats! :)
I noticed you're still working with polymers.

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Sun Oct 08, 2017 3:00 pm

Awesome! I sure hope not too many other people pay thousands to get their OBC replaced or dump their Leaf w/a failed diode.

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Sun Oct 08, 2017 4:35 pm

That is great, thanks for the confirmation that it works. It is concerning that if that fails, it is half the value of the car potentially. This fix (if diode is issue) really takes the sting out of it.
'12 SL with 53K miles.
FL Heat = 8 bars at 41K miles
Battery replaced at 48K miles

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Sun Oct 08, 2017 5:52 pm

I hope to never have to do this, but it's awesome to have such a simple fix explained so clearly! I'm saving this as a PDF in case that slide deck ever disappears from the web...

Here's the URL, in case anyone wants it:!AjONM_UrXWS8-xqfBWuDqcPAFCuK
Vancouver, CA owner of a 2013 Ocean Blue SV + QC, purchased 01/2017 in WA
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Mon Oct 09, 2017 5:15 am

Congrats on the DIY fix. These kinds of things are great examples of where Nissan should publish a an official way to fix it of replacing some expensive part, but also detail exactly what has failed so enterprising individuals can go about repair this way.
Pulled the trigger on going EV on 10/2016 with a 2012 Leaf SL, traded it in and now I'm a very happy Tesla Model 3 owner. Reservations for Tesla Model Y and Cyber Truck.

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Mon Oct 09, 2017 6:22 am

Very happy for you...and thanks for sharing your success with the forum!
2011 Blue Ocean SV w/floor mats & window tint
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Mon Oct 09, 2017 6:46 am

What does the connector in photo #9 energize ?
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Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
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Tue Oct 10, 2017 8:20 am

SageBrush wrote:What does the connector in photo #9 energize ?
I truly have no idea. It didn't seem required for this fix.

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Tue Oct 17, 2017 12:21 pm

Lets look at the protocol:

That wire is the Control Pilot wire. The EVSE sends the information on the available current with a square wave. The "speed" of the wave is the power available. The diode does not have any effect on that.
A 1 kHz square wave at ±12 volts generated by the electric vehicle supply equipment (EVSE; i.e., the charging station) on the control pilot to detect the presence of the vehicle, communicate the maximum allowable charging current, and control charging
Now the diode has 2 effects:
1. Current flowing from the car back to the EVSE is stopped.
2. There is a voltage drop of 0.7v from the EVSE to the car on the square wave. It keeps the same speed but the peak to peak voltage is lower.

According to here (guy building his own EVSE for 30$): ... g-Station/
The EVSE sets the duty cycle and the EV adds resistance from the pilot the Ground to vary the voltage. The EVSE reads the voltage and changes state accordingly.

State Pilot Voltage EV Resistance Description
State A 12 N/A Not Connected
State B 9 2.74k Connected
State C 6 882 Charging
State D 3 246 Ventilation Required
State E 0 N/A No power
State F -12 N/A EVSE Error

So the car "consumes" some part of the 12v by applying a resistor. The value of the resistor thus the voltage determines the state. Remember you`re lowering the voltage 0.7v that what the spec says.

It seems like there should be no effect because the pilot voltages steps are much bigger than the 0.7V. Maybe it does this because the 12v is not calibrated on the EVSE side or the resistors don`t have a good enough tolerance.

By applying a voltmeter (or better a spectrum analyser) on that wire while charging you could see exactly where the problem is and how to properly fix it.

If the diode does the trick, it`s probably a tolerance issue on your car or the EVSE or both and lowering the voltage brings you back on track.... anyway I don`t think (disclaimer if you car burns I`m not responsible) there is anything bad that could happen.

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