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Getting Diode check error and Vent Required

I sent a support ticket in too.

However, if anyone has ideas, please let me know.

J1772 was plugged into car and I got GFI errors. Then unplugged it from car and then got diode check errors and vent required message. Tried disabling those checks and then noticed sparking on the wires entering my J1772 plug. The cable had got damaged due to ice/snow/rain and lack of an adequately long enough strain relief. Flipped the breaker and removed the OpenEVSE and repaired the burnt wires/cables (soldered them at work and covered with heat-shrink tubing and electrical tape). Plugged OpenEVSE back in and it booted fine but then I restored the diode error and vent check options and now I'm getting those errors again, without plugging into the car. I opened up the OpenEVSE and don't see any damage inside.

Any ideas?

Thx, ...Roger

We would recommend checking the DC/DC power supply and the pilot OPAmp circuits for damage. The DC/DC should be outputting -12v and +12v DC.


ok, I'll check those voltages out Chris.


Ok where can I find schematics to probe signals? I found one picture but it doesn’t show 12V or -12V outputs. Also DC power supply mentions 5V and 12V supply outputs but nothing about a -12V supply. Anyway I did find 12V on one pin on a blue screw strip on the main board and I found 12.9V on a pin on the display/processor board. 5V supplies to the 8 pin ICs seem fine too. Only have a DVM at home but could borrow a scope from work. Will pilot square wave be active even after diode check fails? Roger

Schematics are located here. 

Did you figure it out?

I'm facing to the same error trying to charge my Renault Kangoo

I had to change my controller. OPENEVSE gave me a discount which was nice. It’s up and running now.

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 Thank's for your answer Roger.

I just receive a new box and test it with my Kangoo.

I hop that it's not a fail of the controller.

By the way, what do you call controller, the display or the board where is plugged the coils ?

If your OpenEVSE is new, I’m sure the support team will help you. The controller is the main board that connects to the relays, to the current sense coil, to the display, etc.. it has the approx 1” square plastic unit on it. I think I have the vent check disabled. That is only required for very unusual EVs that use lead acid batteries. Roger

 I found my problem !!!

I was the delivered cable with plug type 1

The pilot and proximity were reversed. I had to cut the cable and dismount the plug to reverse the pin.

Bad quality of product from open-EVSE

Fortunately no damage to the car nether the charger.

For information the pilot (pink cable) should be on the left looking to the plug with ground on top for plug type 1.

Plug type 1

Did you ever open a support ticket with a OpenEVSE?
Great that you debugged it though!

Yes I did open a ticket but the answer did give me a solution, ground and pilot were well connected:

Hi Pascal,

Both Diode Check and Vent Required have to do with the Control Pilot. Ensure you have the correct wire connected to the control pilot and the controller is properly grounded.


We are sorry to hear there was a problem with our product, the J1772 Type 1 cable. During trouble shooting we have to explore possibilities starting with the most common. We do not always get it right on the first pass.

We have notified our supplier and have inspected all units on hand. All units in stock have tested good. It appears the assembly error was an isolated issue.


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