“I-Key system error” (or fault) in Nissan cars – here’s how to fix this

The “I-Key System Fault” error message (also says “Error” instead of “Fault” in some models) is all about the connection of your key with the BCM module. BCM stands for Body Control Module and it controls a whole lot of functions including the keyless system.

While sometimes the reason for this message to pop up on your dash is just the low or dead key fob battery, very often the problem may be much more complicated to locate and solve.

Let’s see what can happen and how you can fix this!

The reasons for the I-Key system problem

Nissan cars have really complicated electronics today. Once even some small thing goes wrong, the entire system may malfunction and start throwing one warning after another.

The I-Key system is totally dependent on the BCM, so I would start searching in this field. But at first, you should check the most obvious and simple things.

Here are the reasons that can trigger this warning:

1) Key fob battery is dead

In a keyless-entry car, the battery in the key fob will last about 1 year or even less than that. It constantly powers the chip that constantly sends its signals, so the life expectancy of the battery is pretty short.

In this case, it may also say “Key ID Incorrect” or also “No Key Detected”.

2) 12V battery is about to die

It’s not uncommon to see the I-Key warning in a car where the 12V battery is low. Remember that in hybrid and electric vehicles, the BCM is still powered by the 12V battery, so it can be the reason for their problems. But, of course, this article is not only about EVs.

If the battery reads less than 12.5V, there is a chance this is the culprit for your problems.

3) BCM module damage

First of all, it can be damaged by water intrusion. It’s quite hard to get to the BCM unit in many Nissan cars. I’ve tried to do this in an old Leaf and I had to take off some trim plastic. I found that the block is very poorly located and any moisture or condensate water can easily damage its connections.

4) Battery contacts or ground cable problems

Sometimes, the terminals on your battery may get dirty. White or green buildup will prevent them from working properly. Also, the cable that is connected to the negative terminal of your 12V battery, has another connection that’s called ground. It can get dirty, corroded, or affected by water.

In any of these cases, there will be anomalies with voltage in your car, so the I-Key system may throw the warning.

How to fix the problem?

Fixing the issue on your own is possible, but in some cases, you will still need professional help.

If I had this problem with my Nissan, I would start with the easiest-to-check things and would proceed with some harder possible reasons.

Let’s see what you can do:

1) Replacing the key fob battery

One of the obvious and cheap ways to try and solve the I-Key system error problem is to replace the key fob battery. Take the key fob apart and see which type of battery you have there. Usually, they are CR2032 or some other widespread type you can literally buy in any supermarket.

Replace the battery and try opening and starting your vehicle. Chances are you will not see this nasty warning again.

2) Disconnecting the 12V battery

There is still a chance that the I-Key warning is just a glitch of the electronics. So, you can try fixing it by disconnecting the battery.

Disconnect both cables for 5-7 minutes and reconnect them back to see if the problem is solved. Sometimes, this will help you fix the issue for a limited period of time only.

3) Checking the 12V battery

If you have a multimeter available, check the voltage of the battery. It should read 12.5-12.6 volts. Anything lower than that will mean that the battery is not full of juice. You may use a jump starter or battery charger to bring the battery back to life.

If the battery is older than 4-5 years, it would be nice to just replace it with a new one. It will anyway start malfunctioning very soon.

4) Check the BCM

If you have the tools and wish to dig deeper, locate your BCM and have a look at its connections. You will need to see the repair manual for your car (find it online).

If the connections are wet, dry them and try reconnecting the module. Also, you may want to ensure that water will never disturb the BCM again – pack it into something or verify water will never get there again.

In some cases, the BCM may be dead. In this case, nothing in your car will actually work.

5) Ask for professional help

It’s pretty obvious that if nothing helped you solve or at least locate the problem, there are no more DIY ways to tackle the I-Key warning message. In this case, just don’t waste your time and go to a good Nissan dealership or to an independent shop for help.

Using the codes stored in various modules and also their own experience, mechanics will quickly find the actual culprit.

Can you still drive your Nissan?

When you see the I-Key system error message, it’s 50/50 whether you can start the engine. While in some cases, the engine will crank and the car will come to life, in some other situations, the car will be completely dead.

Even if you decide to drive a car that has successfully started but has this message on its dash, be careful. The entire electrical system may go off at any moment!

When there is no way to start the engine, of course, you can’t drive.

Also, make sure you don’t leave your car open. The central lock may not be working, so you will need to disconnect the battery and use the manual key to lock the doors. Fortunately, your Nissan has the metal key hidden in the key fob and the keyhole in the driver’s door. For all other doors, you will need to lock them manually from inside.

How much is it to solve the problem?

Well, it can cost you as little as $1-2 if it’s just about the battery. Or it may be free if the battery disconnection method will help you. If you decide to go to the dealership, diagnostics will cost at least $100-$150 and then they will charge you more money for the repair.

I strongly recommend trying all DIY methods first before you decide to ask for any help from the dealership.

Do you have any experience fighting with the I-Key warning? Please write in the comments below!