Codes U0121 and U1002, will not start with key, but will with remote start?

Hello KBEAUCH16,

Sounds like the immobilizer may be being affected because of a fault with the ABS module.

I would first sit in the vehicle and push the start without stepping on the brake. Then push and hold again without pressing the brake and see if the dash lights up. If so, the immobilizer is recognizing the key.

So, we can put an issue with the immobilizer on the back burner.

If not, it should say key not detected.

Do you have an AEB warning light on? This is the Automatic Emergency Braking system. If this light is on, then the system is disabled.

It looks like code U0121 is set if the distance sensor detects and error signal that is received from ABS actuator and electronic control unit via CAN communication, the Controller Area Network. This allows modules to communicate with each other.

The other code U1002 pertains to the ABS and electronic control unit is not transmitting or receiving communication signal for 2 seconds or less.

Seems like it may be an issue with the ABS actuator.

Once the vehicle is started with the remote start, are you able to get in and drive it or does it shut off on you?

When I worked at Nissan, we replaced tons of these. Unfortunately, they are over $1,600.00, just for the part.

There have been 3 recalls for this part but from what I can see only pertained to the Maxima, Murano, Pathfinder, and Infiniti QX60.

This doesn't mean it hasn't been revised though. If you send me your VIN, I can look it up with the National Highway Traffic Safety Administration. This will aid us in diagnosis. I will need the entire 17-digit vin.

Also, what do you have for a scan tool? Is it a code reader or can you perform tests with it?

Testing this requires either a Consult III, which is the Nissan dealer scan tool or a scan tool where you can get into the ABS and Radar system and run diagnostic procedures.

A multimeter will be needed as well, do you have one?

We can check some things with the multimeter but might end up needing the scan tool depending on what we find.

Let me know what you have available to you for tools so I can get some test together for you.

Here is an article on some symptoms of a failing ABS module:
https://www.2carpros.com/articles/7-common-symptoms-of-a-bad-automotive-abs-module

Check it out just for the information.

The only reason I can see the vehicle not starting with key to me would be an issue with it reading the key, however there may be a fail-safe put in for if there is an ABS fault, the car cannot be started because of the issues with the Automatic Emergency Braking System. Nissan has actually been sued for it in 2020.

There also may be two separate issues but we need to go with the codes we have, so don't erase them, please.

So, answer the few questions for me, let me know what you have for tools, provide you VIN please, and please let me know if there was any work done recently or there are any other lights on or problems.

I am adding a TSB for key not detected/engine will not start. Go through it and see if you have any of the symptoms in it. (Sorry it was kind of large, so I had to add it in multiple photos)

Also, if you have any devices in the car that has been added, please remove them for now. Anything that puts out a RF signal, for instance Bluetooth devices, phone chargers, Apple Air Tags, toll transponders like E-Z Pass anything electric or wireless can interfere with the Nissan Anti-Theft System or NATS and cause the vehicle not to start. If you have added anything that did not come with the car, remove it for now.

Thank you,
Brendon