2015 Altima no start key fob issue - Help!

[JeffKeryk]

My friend's 2015 Altima has the infamous problem of not recognizing the key fob.
It is not the fob battery; I replaced it but doubted that was the problem as the door locks and everything else worked.
When working correctly, the fob onln needs to be inside the car, even in the trunk, to be recognized.
For the last few months Dan would hold the fob next to the start button and the car would start.

Now it is very intermittent; it does not recognize the key in the morning but does in the afternoon.
I suspect a major module or even the ECU. Not sure how to check...

Any guidance is appreciated.

 

[TheOilWizard]

Start with the key.. Is it possible the key is the problem? Is there another key your friend can test with?

 

[JeffKeryk]

Start with the key.. Is it possible the key is the problem? Is there another key your friend can test with?

No key. It's a key fob and button start. This is a computer component problem. But thanks!

 

[javacontour]

No key. It's a key fob and button start. This is a computer component problem. But thanks!

Yes, is there a 2nd key fob they can use for testing?

 

[TheOilWizard]

No key. It's a key fob and button start. This is a computer component problem. But thanks!

I understand that. I said "key" as a generic term. Can you test another FOB?

 

[atikovi]

Doesn't it have a slot in the dash for the fob?

 

[The Critic]

https://static.nhtsa.gov/odi/tsbs/2021/MC-10192011-0001.pdf

 

[KGMtech]

Body Control Module has entered the thread.

 

[JeffKeryk]

https://static.nhtsa.gov/odi/tsbs/2021/MC-10192011-0001.pdf

The key fob functions properly; the only problem is starting the vehicle. When working, like it did this afternoon, you have to hold the fob next to the start button. If you hold the fob at normal length, no dash lights, no nothing.

 

[JeffKeryk]

I understand that. I said "key" as a generic term. Can you test another FOB?

Only have 1 key fob.

 

[JeffKeryk]

Doesn't it have a slot in the dash for the fob?

View attachment 215756

I will have to check. But this is to reprogram the fob; I don't think it is a fix to the starting issue.

 

[Passport1]

My Suzuki and Mitsubishi Outlander have the same issue. The Mitsubishi will itermittently flash 'key not detected' while the engine is running, car in park and either front door is opened then closed. Holding the fob close to the start button usually clears the warning.

Gobs of sehnsucht for the days of a key and column ignition switch.

 

[JeffKeryk]

My Suzuki and Mitsubishi Outlander have the same issue. The Mitsubishi will itermittently flash 'key not detected' while the engine is running, car in park and either front door is opened then closed. Holding the fob close to the start button usually clears the warning.

Gobs of sehnsucht for the days of a key and column ignition switch.

No warning message; there is no communication. It is like the key fob is not in the car.
I will go over in the morning and do another test. He says it does not work in the morning but does in the afternoon.
You have to put the fob next to the button for any chance...

I've seen on Youtube striking on a module under the dash may "awaken" it.

 

[zzyzzx]

I'm adding this story to my list of reasons to never own push button start.

 

[atikovi]

Only have 1 key fob.

That's not a good idea. Lose that one fob and chances are you have to get the car towed to the dealer to have the security module replaced in addition to a new fob. A $200-$250 fob turns into $800 or $900 repair.

 

[SHOZ]

On Hyundais the problem seems to be slight bit of corrosion on the fuses controlling the key recognition and always hot base system. Happened to me with my PB start Gen Coupe and also on the older Accent for the radio.

The fuses check out as good but if you notice any difference in voltage on the other leg then there is some resistance there.

 

[TheOilWizard]

That's not a good idea. Lose that one fob and chances are you have to get the car towed to the dealer to have the security module replaced in addition to a new fob. A $200-$250 fob turns into $800 or $900 repair.

Absolutely. Not to mention if it's your primary vehicle, you'll be needing a rental. Around here, at least, shops are backed up a week before they'd be able to get to it.

 

[JeffKeryk]

Yesterday I removed and replaced the brake light switch, as this can be a cause.
The Altima started right up this morning. I doubt this is the end of the story...

 

[dogememe]

I would suggest getting a 2nd key/fob immediately. Just my personal opinion but not only is that key to have around in case you lose one (no pun intended) but it'll serve as a useful diagnostic device to determine if the existing fob is bad or the issue is something else.

 

[mk378]

When you put the fob near the button, it is read by a near-field radio which is a completely different system.

There are three types of communication:
1 outside the car to unlock the doors
2 inside the car (e.g. driver's pocket) to allow starting
3 near the button as a reserve way to allow starting

I don't know if 1 and 2 use the same radio system or not.