I-Key System Fault

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Well-known member
Dec 17, 2012
Central Massachusetts
I-Key system fault.
I’ve gotten this message twice now in the past month in my 2015 S.
The first, a couple weeks ago, occurred halfway through the start up jingle, with a clunk under the hood.
The second, just yesterday, but I didn’t notice any sound due to ambient noise.
Both times was over 90 degrees F outside and I was either already rolling down the windows or the a/c was already on during start up.
I get a bunch of DTCs and the car won’t shut off and tells me apply the parking brake.
Researching MyNissanLeaf posts and other forums, I find a variety of possible causes.
I can eliminate the 12v as it’s new, all the connections including ground are clean and LeafSpy shows it healthy with no parasitic drains.
Both FOB batteries have been replaced and they each work normally.
I see no evidence of water ingress anywhere or obvious relay damage.
I suspect a bad relay, but it could also be the IPDM, or something else entirely.
Both times I was able to clear the DTCs and then it worked normally.
Although, I had to clear the lower DTCs first.
They’re in alphabetical order.
I could only clear ABS and Brake last.
By the time those two remained, I could shut the car off.
I have no experience pulling and testing relays, but I intend to learn. Any tips would be appreciated. I’m already researching this online.
I’m not sure which relay is the ignition relay or how exactly to test it with my multimeter.
No idea if I can test the IPDM, but it seems to be a simple plug in operation.
I don’t hear any unusual noise under the hood such as relays clicking.
I’d rather not start replacing things without knowing if it’s the cause.
I try to avoid the dealership except as a last resort.
At this point it’s random and occasional and I can rectify things with LeafSpy, thankfully.
It’s 8 years old and just passed 50k miles, so it’s not entirely surprising.
At least others have reported similar problems.
Thanks for any suggestions.
I’ll update this post as developments progress.
>C118C 0109 ABS EV/HEV System BRC-126
Ok None---> AIR BAG
B2604 0008 BCM Shift PN Diag CAN SEC-81
>C1A6E 0109 BRAKE EV/HEV System BR-146
>C1A70 0109 BRAKE Brake Control System BR-160
Ok None ---> CHARGER
Ok None ---> EPS
>P3187 000B EV/HEV Elec Shift System EVC-257
Ok None --> HVAC
Ok None ---> HV BATTERY
Ok None ---> IPDM E/R
Ok None--> METER
P18A7 0008 SHIFT
Ok None ---> VSP
Another old post I found on here suggests it might be the shift.
But with the clunking sound on start up, I think it’s more likely a relay wearing out.

But on looking at the DTCs more closely, maybe it is the shift, though don’t see why, except one post showed someone disassembling it and found tightly bound wires. Their problem resolved by loosening them.

At least the IPDM was okay.
I had one of the small relays (in the relay panel under the hood, on the passenger side, high on the firewall) intermittently fail to drop out. It caused TCM error messages on the dash (transmission control module errors) because it was keeping one 12V power source to the module energized when the car was off. This would drain the 12V battery if the car was parked for too long. Several of the relays are the same configuration so you could purchase one new relay and try it in each position until you eliminate the problem. Given your symptoms and the DTC's, I do suspect a relay failing to drop out. You cannot reliably test them because the act of removing the relay from the socket will jar it enough to cause it to drop out. I felt the failing relay drop out when I removed it from the socket so I purchased a new relay and had no more issues.
Thank you.
Do you have a link or part number for the relay?

I’ve gone 3 days with no issues, but once something starts to it’s only a matter of time.

I’ve found a few good looking relay pullers for sale under $10.
DNAinaGoodWay said:
Thank you.
Do you have a link or part number for the relay?

I’ve gone 3 days with no issues, but once something starts to it’s only a matter of time.

I’ve found a few good looking relay pullers for sale under $10.

I don't have the part number, but I remember the people at the Nissan parts department had trouble finding it in their system. I am able to pull those relays out of their sockets just using my fingers (without any special puller). I am sure they are standard relays used in many different vehicles so you might find them cheaper at an auto parts store or electronic supply warehouse.
I’ll try to create an itemized list of the relays in the various boxes they’re in, to identify how many different types there are.
I suspect it’s the ignition relay which I think is in the big box above the 12v battery.
I might get one of each type to have on hand.