2017 Leaf S - I-Key System Fault and LOTS of DTCs

I got a message for an "I-Key system fault" on my 2017 Leaf S that started yesterday. It appears on my display when I start driving, goes away after driving a while and then comes back occasionally. It doesn't seem to affect anything in the vehicle except for the annoying message. Based on other threads it seems like this is often caused by a weak or dying 12v battery.

I disconnected the battery terminals to clean them (they had lots of corrosion on both the positive and negative) and I fully charged the battery. It tests with a multimeter at 12.8V, but I haven't load tested it.

I pulled the DTC codes using Leaf Spy Pro and found the following:
Ok None ---> ABS
Ok None ---> AIR BAG
>B261A 0008 BCM Push-BTN IGN SW PCS-58
B2626 0008 BCM Outside 1 Antenna DLK-71
B2627 0008 BCM Outside 2 Antenna DLK-73
>B26FC 0009 BCM Keyfob Miss Registration SEC-90
C1707 0008 BCM Low Pressure RL WT-26
Ok None ---> BRAKE
Ok None ---> charger
Ok None ---> EPS
Ok None ---> EV/HEV
Ok None ---> HVAC
Ok None ---> HV BATTERY
Ok None ---> IPDM E/R
Ok None ---> METER
Ok None ---> MOTOR CONTROL
Ok None ---> SHIFT
Ok None ---> VSP

Is it worth it to clear the DTC's and see if cleaning the battery terminals and charging the battery fixed the issues?

I'm going to replace the battery with an AGM battery, and am looking at putting in a group 35 battery since it should fit the tray... would I need a new hold down for this battery or will the factory hold down work?

Thanks!

I checked the 12V battery this morning and it was 12.6V, then a few hours later it was 12.8V... I guess my car topped it up during the day.

I cleared the DTCs and still had the following:
>B26FC 0009 BCM Keyfob Miss Registration SEC-90

Then started driving and the I-Key message reappeared with the following DTCs now being reported:
B261A 0008 BCM Push-BTN IGN SW PCS-58
>B26FC 0009 BCM Keyfob Miss Registration SEC-90

Any ideas on my next steps?

Looks like you need a new 12V battery - low voltage conditions will cause all sorts of odd behaviors with the BCM and other electronic components. The battery is almost 5 years old, it doesn't owe you anything at this point...

Buy a new 12V battery, trickle charge it, then install it in your LEAF. Then, clear all the codes again and post back any codes that return.

Thanks for the feedback. I'll go out today to get an AGM battery and charge it overnight before installing it.

I decided to stick with a group 51 battery to avoid any fitment issues with the battery hold down.

I'll report back if I continue to get DTCs after the battery swap.

Remember: that's 51R or you'll have a hell of a time getting the cables to reach the terminals.

LeftieBiker said:

Remember: that's 51R or you'll have a hell of a time getting the cables to reach the terminals.

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Thanks for the heads up! Fortunately the one I'm getting is 51R, but I didn't know there was a difference so that's very good to know


Edit: Wow... buying the battery was a frustrating experience. The parts guy tried to tell me that 51R was not the right battery, that I should buy a 51 according to their system, and if I bought the 51R it would void the battery warranty! It took 30 minutes of conversation, looking under the hood of my car, showing him the website recommendation from his own store's website, and finally him looking it up in a book to see that his computer system was wrong. It's now on the charger to get installed tomorrow. Double thanks @LeftieBiker for the information on the 51R battery!

I changed the battery then cleared all the DTCs, but the same two codes came back soon after driving.

Then when I went to park everything went crazy - the car wouldn't shut off with the message "when in park use parking brake". If I pressed the power button the Leaf would just start right back up again with that message regardless of whether the parking brake was applied or not

If I powered off then pressed the power button quickly again then the Leaf would power off, but I would get a high pitched beep when I left the vehicle with the key. I had to pull the negative terminal to shut it up.

There were a ton of DTCs thrown as well with EV, ABS, BCM, and Brake. I pulled the battery cable for 20 minutes and then cleared all the DTCs again, hoping that this was a glitch caused by the battery change. The only DTC now is B26FC 0009 BCM Keyfob Miss Registration SEC-90. This one is probably because a local locksmith registered a wrong keyfob and didn't clear it out, so it doesn't concern me as much as the other codes

Car drives and charges fine with messages in the dash.

What is my next step?

Was the new battery fully charged when you installed it? Unlike an ICE car, the Leaf doesn't rapidly charge a depleted 12 volt battery.

LeftieBiker said:

Was the new battery fully charged when you installed it? Unlike an ICE car, the Leaf doesn't rapidly charge a depleted 12 volt battery.

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Yes, I fully charged the battery overnight before installing it this afternoon. Currently the battery is at 12.96V.

Here are the codes that popped up after clearing everything and driving for a while.


Is it worthwhile to pull the negative from the battery overnight, or will that not help anything?

Gerry usually suggests trying the disconnect to reset several times, as once may not work. If you got the codes cleared and they then came back, though, that's another matter, I'm afraid...

LeftieBiker said:

Gerry usually suggests trying the disconnect to reset several times, as once may not work. If you got the codes cleared and they then came back, though, that's another matter, I'm afraid...

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I cleared all the DTCs again and pulled the battery negative - I'll leave it off all night then reconnect in the morning to see if it fixes anything. I also put the battery back on the charger for the night. I am using a different charger in case my other charger wasn't charging properly... it has been hooked up for a few hours and is still charging (at 2 amp setting) so hopefully it is a case of a not quite fully charged battery.

If I still get the warning and DTCs after charging the battery and leaving the car disconnected all night I guess I'll have to bring it to the dealership.

Hooked up the battery this morning after fully charging it again last night and then went for a short drive... so far no warnings on the dash.

I'll drive it more later today to see if the new battery's state of charge was the whole issue.

Update: no warnings after another 20 minute drive.

It can take quite a while to charge a FLA battery at 2A. Glad it was something simple and thanks for the update.

goldbrick said:

It can take quite a while to charge a FLA battery at 2A. Glad it was something simple and thanks for the update.

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Fourth drive of the day and all the previous issues came back. I-Key warning and apply parking brake when parked error.

Is there anything else I should do before bringing it to the dealership?

Replace the 12v?

salyavin said:

Replace the 12v?

Click to expand...

Brand new 12v AGM battery installed yesterday and fully charged.

The "when in park use parking brake" message only appeared after changing the battery.

Is there anything else I should do before bringing it to the dealership?

Click to expand...

Check ALL of the 12 volt cables and connections.

LeftieBiker said:

Is there anything else I should do before bringing it to the dealership?

Click to expand...

Check ALL of the 12 volt cables and connections.

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I wire brushed the connections (both terminal and clamp) before installation, but I'll check them again.

There is a main ground in what looks like just a holding clamp on the longer cable. Check that connection too, along with any other connections other than the battery terminals that you can reach.

LeftieBiker said:

There is a main ground in what looks like just a holding clamp on the longer cable. Check that connection too, along with any other connections other than the battery terminals that you can reach.

Click to expand...

Thanks. I just looked at everything that I could see and reach and all looks good. Disconnected negative as well as unscrewed the wire with ring terminal (is that the main ground?), and disconnected the positive. I sanded and wire brushed them all clean (including the battery lugs), then reinstalled everything. There was some corrosion on everything, so I made sure all the connections were back to shiny metal.

It's getting dark so I'll check everything again in the morning.