Ghost Alarms - Help Me Find A Solution (Solved: Passenger Side Hood Latch Mechanism)

[Ilya]

Received the new door switches and replaced all four in like 5 minutes (man, love jobs like that). Locked the car...lets see what happens!

[Ilya]

Alarm was fine rest of the day Monday and all day today until just now. Within the last 35-40 min, it has gone off twice. UGH!

[Ilya]

Happened again today while I was at a restaurant. I've been leaving the car unlocked at home (live in the country so not too worried).

[VStar650CL]

Aargh. This is why all the latest models have a "cause of alarm" function in the BCM so technicians can sort out false alarms. It just took Nissan decades to discover the need for it.

The other things which can trigger it on most models are the hood switch and trunk switch, and of course damp wires anyplace in the car. Part of the problem on all models is that the BCM pullup resistors on the door and other switches are usually very weak, typically 10K ohm. That means it only takes a little bit of leakage to pull the signal toward ground and make the BCM think a switch is closed.

[Ilya]

When did the 'cause of alarm' thing become available? Is it available on my car if I had the dealer scan it with CONSULT? If so, I wonder if that Foxwell NT710 "Consult Like" device for $249 that was discussed in the Forest Air Scent Cartridge thread may be able to see the "cause of alarm" and I could self service this.

I also just merged this thread with my-11-m56x-is-possessed-alarm-randomly- ... 20812.html which I just remembered I had already started. Going to try and keep these together as they are the same issue. Looks like in that thread we couldn't find out where the hood switch is, etc.

[VStar650CL]

The FSM says your M does have it. It will be found in BCM -> Theft Alarm -> Work Support. It's a 1-trip function showing the cause of the last alarm event, any new event overwrites it.

The harness layout shows the hood switch on the passenger's front of the engine box, but I can't find a drawing of the exact location. It's the only body switch monitored by the IPDM and not the BCM.

[Ilya]

The FSM says your M does have it. It will be found in BCM -> Theft Alarm -> Work Support. It's a 1-trip function showing the cause of the last alarm event, any new event overwrites it.

The harness layout shows the hood switch on the passenger's front of the engine box, but I can't find a drawing of the exact location. It's the only body switch monitored by the IPDM and not the BCM.

Will have a look - I did go through and lube up (with spray liquid wrench lube) the front hood locking mechanisms as well as the rear trunk - as one video in this thread suggested to do. Forgot to do the doors but will do those tomorrow.

I imagine the hood switch is similar in design to the door ones I replaced? Meaning, the hood physically touches it and pushes it down? I remember the 4th generation Maxima's I had had a switch like that on the front radiator support on the drivers side.

[VStar650CL]

Frankly, I dunno on an M. I never had to deal with one. Nissan ones are usually integral with the hood latch, but from what the harness layout for the M showed, I think it's probably a separate piece. It appeared too far to the right to be part of the latch.

[Yoda's Master]

Have you tried cleaning your grounds? idk if it'll work

[emm3seven]

When did the 'cause of alarm' thing become available? Is it available on my car if I had the dealer scan it with CONSULT? If so, I wonder if that Foxwell NT710 "Consult Like" device for $249 that was discussed in the Forest Air Scent Cartridge thread may be able to see the "cause of alarm" and I could self service this.

Chiming in as the resident NT710 owner...

I don't see any indication of support for this kind of function in Foxwell's "supported functions" database. Sometimes the menu options are organized weirdly, but if the alarm system is primarily a BCM function, then the only option listed in the scan tool menus is a generic "read codes" and "erase codes" for BCM.

Caveat, I didn't actually set off my alarm and then go poke around in the menus...if I get a chance to do that I'll update with a final confirmation.

[Ilya]

Have you tried cleaning your grounds? idk if it'll work

Will add it to the list! I did do it a few years ago but it's time!

When did the 'cause of alarm' thing become available? Is it available on my car if I had the dealer scan it with CONSULT? If so, I wonder if that Foxwell NT710 "Consult Like" device for $249 that was discussed in the Forest Air Scent Cartridge thread may be able to see the "cause of alarm" and I could self service this.

Chiming in as the resident NT710 owner...

I don't see any indication of support for this kind of function in Foxwell's "supported functions" database. Sometimes the menu options are organized weirdly, but if the alarm system is primarily a BCM function, then the only option listed in the scan tool menus is a generic "read codes" and "erase codes" for BCM.

Caveat, I didn't actually set off my alarm and then go poke around in the menus...if I get a chance to do that I'll update with a final confirmation.

Appreciate it!

[Q70sGuy]

When I brought mine to the dealer they said the « last alarm » function in consult showed them nothing. I felt that made no sense but from experience I know not all techs are made equal. They never found the issue but it just stopped happening on its own. I unplugged the hood latch, it didn’t help. I agree with Vstar that there must be some moisture in a wire somewhere but without the consult showing why the alarm triggered I couldn’t pursue further. Let us know what the dealer finds.

[Ilya]

When I brought mine to the dealer they said the « last alarm » function in consult showed them nothing. I felt that made no sense but from experience I know not all techs are made equal. They never found the issue but it just stopped happening on its own. I unplugged the hood latch, it didn’t help. I agree with Vstar that there must be some moisture in a wire somewhere but without the consult showing why the alarm triggered I couldn’t pursue further. Let us know what the dealer finds.

I'm likely not going to take it to the dealer as I think it's going to result in just wasting money for half-assed diagnostics - unless I previously knew a tech who worked at one that I could trust.

Going to try cleaning the grounds and doing stuff like that to hopefully help even 0.000000001%.

[emm3seven]

I wonder if that Foxwell NT710 "Consult Like" device for $249 that was discussed in the Forest Air Scent Cartridge thread may be able to see the "cause of alarm" and I could self service this.

I don't see any indication of support for this kind of function in Foxwell's "supported functions" database. Sometimes the menu options are organized weirdly, but if the alarm system is primarily a BCM function, then the only option listed in the scan tool menus is a generic "read codes" and "erase codes" for BCM.

OK, so I've learned something! The NT710 has a lot more options than are shown on the website.

It does support this function:



I was not able to figure out a way to actually set off my alarm so I can't 100% test it, but the function is there and looks very similar to the data from a Consult III. There's a bunch of other BCM special functions / config items in here too that I missed, going to go chime in on that other thread too...

[Ilya]

One way to trigger a 'real' alarm (and not just from the remote) is open the car door from the inside while it is locked - if you can see what triggered it, I will buy this thing immediately! hahaha

But this is promising...thank you!

[emm3seven]

One way to trigger a 'real' alarm (and not just from the remote) is open the car door from the inside while it is locked - if you can see what triggered it, I will buy this thing immediately! hahaha

But this is promising...thank you!

Okay fiiiine, I spent the evening testing/researching it and made a thread on it. It works.

howto-foxwell-scanner-view-factory-thef ... 35012.html

[Q70sGuy]

As I suspected the less-able dealer was not able to figure out how to use the consult function when they did mine. I hope you buy the foxwell and figure it out Ilya and let me know so I don’t have to.

[Ilya]

One way to trigger a 'real' alarm (and not just from the remote) is open the car door from the inside while it is locked - if you can see what triggered it, I will buy this thing immediately! hahaha

But this is promising...thank you!

Okay fiiiine, I spent the evening testing/researching it and made a thread on it. It works.

howto-foxwell-scanner-view-factory-thef ... 35012.html

You da real MVP!

[Q70sGuy]

Just got mine. I got the 510elite because it’s cheaper. Same functions. This is the best day of my (Infiniti owning) life.
You guys will be shocked to find out how many little things you can configure to make your car more enjoyable (ok maybe like a handful but still). Go read those service manuals.
Thanks emm3seven

[Ilya]

Just got mine. I got the 510elite because it’s cheaper. Same functions. This is the best day of my (Infiniti owning) life.
You guys will be shocked to find out how many little things you can configure to make your car more enjoyable (ok maybe like a handful but still). Go read those service manuals.
Thanks emm3seven

This one? https://www.foxwelldiag.com/products/fo ... -scan-tool

It has the same options EMM pointed out? I'd rather buy the cheaper one if I can get away with it, but I must be able to see the last alarm trigger.

[Q70sGuy]

It’s the same, got it on aliexpress. It’s just a much smaller screen and uses buttons instead of touchscreen. The 710 clearly is easier to use and read but other than that it’s the same functions. If you buy it on aliexpress send a message to the seller to install the Nissan Infiniti pack so you don’t have to fiddle with it. It’s like 100$ cheaper than the 710.

| FOXWELL NT510 Elite OBD2 Scanner All System Scan Code Reader Active Test ECU Coding OBD OBD2 Car Diagnostic Tool Free Update
https://a.aliexpress.com/_mq5pXwJ

[Ilya]

I ordered the NT710 on AliExpress for $180 or so and it'll be here in a few days. I need to figure out what's causing it as I need to leave my car at the airport for 2 days soon and would like to avoid a dead battery hah.

Is there any way to disable the alarm (but still let the car lock/unlock) temporarily? I think I tried to pull fuses years ago, but the lights still flashed. Is there a better way?

[VStar650CL]

You can always just pop the negative battery terminal after locking it up, then use the hard key to get back in after your trip and reconnect it.

[Ilya]

You can always just pop the negative battery terminal after locking it up, then use the hard key to get back in after your trip and reconnect it.

Ah, good point! I always forget about that mechanical key...in this case it's a major plus to have that. I'll just go that route.

[Q70sGuy]

The nt710 has an alarm disable in the options. You can use that once you get it

[Ilya]

The nt710 has an alarm disable in the options. You can use that once you get it

Oh,

[Ilya]

Thanks to the awesome guide that emm3seven posted on the Foxwell NT710 (howto-foxwell-scanner-view-factory-thef ... b61eb5d3b7), I finally got mine and was able to get the first glimpses of what is causing my ghost alarm.

Before clearing the history, I saw that "generator cover switch" and "door switch - driver side" were "ON"...meaning have previously triggered an alarm. Because I replaced all four door switches a couple of weeks ago, my hunch is that this "generator cover switch" is the culprit. So, I cleared the history and locked the car. Sure enough, a few hours later, the alarm went off and it was "generator cover switch" again. AHA! Gotcha.

So...what the hell is a "generator cover switch"? And how do I fix it?

BTW, after using the NT710, I'm glad I went with this as opposed to the slightly cheaper 510...I can't imagine using buttons without a touch screen, would take forever to get around.

[VStar650CL]

I'd have to think that's Chinglish for the hood switch. The ESM doesn't show any other switches besides the doors, trunk, and hood. The hood switch is actually the only one which isn't monitored by the BCM, instead it's wired to the IPDM and gets to the BCM via CAN. Kind of a weird setup, but it's used on lots of models.

[emm3seven]

Awesome to hear that the guide (and the scanner) are helping you get closer to an answer!

I agree with VStar, in the context of the security alarm causes, “generator cover” must be a poorly translated version of “hood”. The SEC section of the FSM has a diagnostic procedure for the hood switch (page 136 in the 2011 version) and I think the Foxwell can even do the realtime read of the switch status as seen by the IPDM if you wanted to try a wiggle test or something.

Coincidentally, I just finished a cleaning and overhaul of the entire hood latch system on my M today as part of replacing a stretched hood latch cable that was preventing the hood from popping. I believe the hood switch that feeds into the IPDM is integral to the passenger side hood latch, based on the connector I saw there, so firing the parts cannon on a new (or gently used) latch could be an option. It’s not too bad to swap.

[Ilya]

So you're saying the hood switch is on the passenger side Hood Lock? DLK-170 in the FSM? I'll buy a new one right now - after 5-6 years of this nonsense, I ain't playin games! lol