DTC U1027 / Charger error

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BillAinCT

Well-known member
Joined
Dec 2, 2021
Messages
151
Location
West Hartford, CT
I went to DCFC just now and the EVSE (EVgo I've used before) said Problem with Charger. I tried both stations. I had my Wifi OBD2 and it's reading U1027 2408 Charger. I'm not finding much about these codes. I read removing the 12V battery and trying again might work but I don't have tools.

The first time I plugged in the CHAdeMO connector, I heard the normal clicking. But no blue lights and EVgo threw the error. And no clicking thereafter inserting the CHAdeMO.

Dilemma: I have enough miles to get to the closest Nissan dealer or to get home. But I can't go home to test and try the 12V disconnect and still make it to the dealer (just my luck).

I'm leaning toward just going to the dealer. But do these charger faults happen that often? Will clearing it fix it?

I cannot clear the codes at the EVSE because LeafSpy Pro (iOS) doesn't finishing reading the codes. It hangs and it doesn't let the Clear DTC codes button function. My BT OBD2 is home where I could try to clear this code and see if I can recover.

Any ideas? Thanks!
 
Probably too late to help, but I know one of my apps has the ability to clear codes, and you can select which ECUs to scan. I think that feature is mainly there to save time, but if you have an ECU that is hanging (and that isn't the one that needs the code to be cleared), it may work around that problem.

It's called Car Scanner, from CarScanner.info.
 
The "Uxxxx" DTCs are related to faults with the CAN buss communications, sometimes these can be caused by a weak or worn 12V battery. In your case with a new car that would not seem likely.

Since the EVSE also gave you a communication fault notice, then the CAN buss traffic between the EVSE and the OBC was likely somehow corrupted. A fault on either their side, or on your side, would possibly lock it all up in a no-charge condition and set a DTC.

If the car were older and out of warranty then it might be worth investigating and troubleshooting, but with a new car warranty might as well let the dealer take a look. It's likely a simple reset needed.

Some Chademo chargers seem to have issues with the CAN communications across various EV models; not sure that i've ever seen the CAN details revealed for Chademo.
 
I gambled and drove home. The Leaf is charging with my EVSE. This gives me time to try clearing the code and try a different DCFC. I suspect it's going to be my charger. There is only one certified Leaf tech at the dealer and they need 2 hours to run the "full diagnostics" of my car. Really?

Is it possible that the fast part of the charger could fail? I would think once the AC is converted to DC then it's using the DC part of the charger.
 
BillAinCT said:
The Leaf is charging with my EVSE. ... I suspect it's going to be my charger.
No, since you're charging at home, your On Board Charger is working fine.

There is only one certified Leaf tech at the dealer and they need 2 hours to run the "full diagnostics" of my car. Really?
That does sound suspect.

Is it possible that the fast part of the charger could fail? I would think once the AC is converted to DC then it's using the DC part of the charger.
No. After rectification (AC -> pulsating DC), there are quite a few stages in the AC charging path, and there is very little in common with the DC fast charging path.

The only parts unique to fast charging are the CHAdeMO connector and cables (HV and quite a few signalling), the CAN bus handshaking logic and circuitry (likely not in the OBC module), the two DCFC contactors, and a small path from the DCFC contactors to the battery cables.

My guess would be the small part of the VCU (or other ECU) where the handshaking / signalling occurs between the vehicle and the DC fast charger. Next guess would be the contactors, or associated cables, or coil drivers.
 
A fellow I work with that had a Gen 1 suggested the EVgo device was bad and it's not the Leaf. Since I tried both EVgo devices I was pretty sure it's not that. I'll schedule with the dealer when I can bring a laptop and wait there. And if they have a CHAdeMO I'll try it.

Thanks for the details. I wasn't aware L2 and DC were so different.

I used 2 BAFO OBD2's which I thought were good ones. Both BT and wifi will read battery state. I also have an Innova $90 reader and it won't even link up with the Leaf. :|
 
The dealer tied me up for 2 hours just to clear the code. :x Had Leaf Spy iOS worked I could have cleared the code and retried charging while I was still at the DCFC. I need a program for iOS to clear the codes so next I can do this myself. Lesson learned.

The dealer tells me it threw the code because "you weren't using a Nissan charger". I said I was at EVgo that I've used before. He said, "Well it's a third party charger". I asked what was I supposed to do? He said, "You can try to clear the code yourself and try again. Once the code is set it will never try to charge." That's BS to me. So Nissan Leaf owners need to carry an OBD2 dongle and expect to clear codes should the EVSE throw a CAN fault.

I'm completely unhappy how this played out.
 
BillAinCT said:
The dealer tells me it threw the code because "you weren't using a Nissan charger".
That is BS

If an important DTC is present, I can imagine it preventing charging as a safety feature
 
BillAinCT said:
The dealer tells me it threw the code because "you weren't using a Nissan charger".

Ridiculous. Both J1772 and Chademo are industry standards. There is no proprietary "Nissan" standard.

I'm still wary of the problem being related to the dongles acting up on the CAN bus. Every time I have used LeafSpy to clear codes it worked just fine. So unless there's a known bug in the current version or incompatibilities with newer LEAFs, I'd still lean towards the dongles. I do know that not all dongles work well with LEAF and/or LeafSpy. There are threads on the forum discussing which dongles work well. In the meantime I'd just leave the OBD2 port free.
 
Nubo said:
Ridiculous. Both J1772 and Chademo are industry standards. There is no proprietary "Nissan" standard.

I know. As much as I wanted to scream BS at the fellow, he's the desk jockey bringing me the paperwork telling me what he's told. "All is fine. We cleared the code, it's charging and stayed clear". Ok, but that was known 15 minutes in. I didn't drop in, I had an appointment. Taking 1 3/4 hours just made it worse.

Nubo said:
I'm still wary of the problem being related to the dongles acting up on the CAN bus. Every time I have used LeafSpy to clear codes it worked just fine. So unless there's a known bug in the current version or incompatibilities with newer LEAFs, I'd still lean towards the dongles.

iOS LS PRO doesn't work at least on a 2022. Reading the DTC codes hangs. It can be restarted clicking "Read DTC" but since it doesn't finish, it doesn't enable the "Clear DTC" button. I have BAFO BT and Wifi versions of the dongle - I know LeftieBiker uses one of these. I just don't have an android in my car so I bought the Wifi dongle and LS Pro iOS to use my iPhone. I took a chance seeing iOS LS is 3 years old and saw other features don't work. Had I known clearing codes was one I would have stayed clear.

I've tried several iOS OBD2 programs. There are some with potential. One shows all the battery info and temps but it doesn't have the math right so SOC is wrong. But all the cell voltages, shunts, and temps are correct. I can still use LS Pro for SOC/SOH but I need an iOS program to read and clear codes so next time I won't be stuck.
 
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