Hello Internet,

I have a problem: my Panic Alarm keeps going off randomly. It started about six months ago with no rhyme or reason. I have done a few things already that are documented in this thread, but I want to start a fresh one to find a solution and hopefully help others in the future since I'm aware that this affliction affects others but there is no known cure yet.

The Facts:

• When I use the Fob to lock the truck, the Panic Alarm with go off randomly. Sometimes once a day, sometimes six times in a 24 hour period. Sometimes not at all for three or four days. Weird.

• When I use the key to lock the vehicle, this condition doesn't happen.

• Vehicle has a dual battery system, starting and house. House battery is electrically isolated from starting battery. Starting battery rests at 12.6v and house battery rests at 12.8v.

Solutions Taken So Far

• Purchased bluetooth code reader on Amazon in conjunction with EngineLink for iOS, no codes being shown.

• Dealership removed aftermarket alarm system. Condition continues.

• New batteries put in both fobs, thinking it was low voltage condition in fob. Didn't solve it.

• Battery taken out of fob #1, leaving fob #2 "live". Condition continued. Battery taken out of #2, leaving #1 "live". Condition continued.

• When I leave the battery in the fob within range of the truck, but lock the car with the key, the panic alarm doesn't go off.

• It was suggested that the fobs are sending the signals on their own, but what are the chances that both fobs would go bad at the same time?

• Hood latch replaced. Condition continued.

• Drivers door courtesy switch replaced. Condition continued.

• Car locked with fob with driver's door open, but courtesy switch pressed down then released -- alarm does not activate but dome light turns on. This step was repeated for each door and doing this does not activate the alarm.

So that's where I'm at. My next steps are going to be to replace the remaining three door courtesy switches and the rear tailgate latch since the Shop Manual indicates that they (along with the engine hood courtesy switch) are part of the the Theft Deterrent System (pages TD-1, TD-2, etc.)

I would love to hear any new ideas out there!


Thanks team!

I'm betting it's an issue with the security system itself. Like the CPU/motherboard that controls it. Not sure if that is tied into the anti-theft system or not, as in the flashing red icon above the HVAC controls when the vehicle is off. You would have to dig into wiring diagrams to find what the panic alarm is hooked into.

Yeah, I'm thinking the same thing--problem with one of the ECU's. A reputable alarm shop I went to suggested to replace all those courtesy switches first before swapping out ECU's. Hood & one door have been replaced. Three doors and the trunk to go.

Update: I replaced the remaining courtesy door switches and the back liftgate mechanism/switch on Saturday 8/5. So now all the "easy" stuff has been taken care of--the four courtesy door switches, the hood latch and the liftgate switch. I also gave the T4R a good wash, hoping to replicate the fact that the alarm seems to be going off after a a good rain/wash. 72 hours later and no alarm...yet. Wish me luck!

I think you might have a wire rubbed on the body, not sure how the removal of the old system was done, you might have a tear / break in a wire.
a loose ground inside your vehicle. a weak main battery. if I were you, I start tracing back, maybe the factory arm and dis-arm wire was used. your kick panel wires.

After replacing the remaining switches three weeks ago, the alarm hasn't gone off. I'm cautiously optimistic that the problem is now solved--one of those switches was bad...?

It wasn't the hood switch and it wasn't the drivers door courtesy switch, since the rando-alarm-going-off problem still persisted after I replaced them. So I said f-it and replaced the remaining three plus the liftgate switch assembly all at once since I wasn't willing to sit through a replace-and-sit-and-wait testing cycle for each one.

Perhaps there was a bad body ground on one of the remaining three courtesy switches? Don't know...the only interesting clue along the way was that the plastic clip that attaches the wiring harness to the courtesy door switch on the rear drivers side slipped right off--meaning that the plastic tab wasn't engaged. Interesting! The function of that switch never failed in the testing lead up to the swap, it performed as advertised meaning it turned the interior lights on/off when depressed, etc. When I replaced it with the new one, I made sure I felt that satisfying "click" when I attached it.

Anyway, feeling cautiously optimistic that I can close this chapter. I hope anyone else suffering from this problem finds this thread useful. Total cost to replace all six switches (hood, four doors, rear liftgate) with Toyota OEM parts from a SoCal dealership: $716.