Key System Error Nissan Altima: Unable To Start The Vehicle

It’s frustrating when you start your Nissan Altima, and the engine won’t turn over as you thought it would. Instead, you get a warning message on the dashboard by saying that there is a key system error. This often prevents the car from starting properly and can leave you stranded. The key system error is one of the most common problems on Nissan Altimas from the mid-2000s to early 2010s.

In this article, we’ll discuss the common causes behind the Nissan Altima key system errors and the steps you can take to diagnose and fix the problem. We’ll cover some troubleshooting steps for the key fob battery, checking for faulty ignition switches, and reprogramming/replacing keys if necessary. 

Common Causes Behind The Nissan Altima Key System Errors

Faulty Key Fob Battery

• The battery in the intelligent key fob remote has likely died. 

• This is one of the most common causes of the key system errors. 

• The fob needs a good battery to be able to communicate properly with the car’s computer and transmit the correct identification codes when starting.

Defective Ignition Switch

• The ignition switch itself can malfunction and fail to synchronize properly with the key fob. 

• This is because the switch communicates wirelessly with the key when starting the vehicle. 

• If it’s damaged or defective, it won’t read the key codes correctly. 

Damaged Key Fob

• The internal antenna or circuits could malfunction if the intelligent key has any physical damage, like cracks or chips. 

• This prevents the proper signal from being transmitted to the car’s computer. 

Key Not Detected Error

• This usually means the key fob battery is dead, but it could also indicate that the key is too far from the vehicle for the receiver to pick up the signals.

Failed Vehicle Control Unit

• The vehicle control unit (VCU) is the car’s computer that manages the intelligent key system. 

• If it has an internal failure, that can lead to key detection issues and prevent the vehicle from starting up.

Faulty Immobilizer System

• Nissans have an electronic immobilizer anti-theft system that communicates with the keys. If part of this system malfunctions, it can lead to no-start issues. 

Steps To Diagnose And Fix The Nissan Altima Key System Errors

• Replace the battery in the intelligent key remote with a new CR2032 coin cell battery, if you find any issues with the battery. Make sure the battery terminals are clean and connected properly. 

• Try holding the fob right next to the driver door handle or steering column to rescan. Also, try scanning while pressing the fob unlock button.

• Look for any cracks, chips or moisture damage on the intelligent key. Make sure the metal key blade retracts fully as well. 

• Have the dealer scan for diagnostic trouble codes that are related to the key and immobilizer system. Codes pointing to specific components can helps to narrow down the issue.

• Wiggle the key in the ignition and try to turn it to diagnose the ignition switch issues. If the ignition seems stuck or only works in certain positions, the switch likely needs to be replaced.

• A Nissan dealer can reprogram and resync your key fobs to the car if they have gotten out of sync. 

FAQs About Key System Error Nissan Altima

Q: Can I override my Nissan Altima if I have a key system error?

A: Some models have a mechanical key release or manual override procedure that can allow the ignition switch to turn on so you can start the engine as a temporary fix. Consult your owner’s manual for more details.