My 2019 Camry with 21k miles has the alarm go off periodically when the vehicle is parked for an hour or more in the sun. The behavior is erratic as one day it could sit out all day and not go off and on other days it could go off after just an hour so so in direct sunlight. The problem has never occurred in cool or cold conditions. The outside temp needs to be at least 70 degrees. Took the car to the local Toyota dealer and they told me they could not properly diagnose the problem unless the alarm went off in their presence. I left it there for eight hours and nothing happened. They did check the battery and said it was a-ok. Had no more issues during fall, winter, spring, but yesterday it went off once and I stopped it by pressing the open door button on the fob. Today it went off twice (temp approx 75). However in both cases the alarm shut off by itsel after about 45 seconds. I took it back to Toyota today, but again the said they could do nothing unless it happened in their presence. The one thing I am trying is to have the windows cracked to lower the inside temp. Any ideas or suggestions would be appreciated.

 

Was the alarm part of a Toyota standard safety package? There should be info in the owners manual.

Find out if the alarm has a window sensor. Drive someplace where the alarm noise will not be a problem. Get out of the car with alarm set as normal. Tap a window and determine if the alarm goes off. If so the window sensor can be a problem. The sensor may have a sensitivity setting to avoid false alarms..

The other alarm switches tend to be on/off type which have less problems. But check these switches. They are linked to the door hood and trunk switch system.

Toyota cars used to have alarm systems with names such as RS3000, RS3200, VIP Security System. The alarms were used in many Toyota models. They were factory, dealer or owner installed (one could by a bolt on system from Toyota).

If you can find out the name of the alarm system, if there is one, there may be a separate and MORE detailed manual for the alarm.

 

Thanks for the input. I looked in the manual and it describes the alarm system but an asterisk leads to a note "if equipped". Since I purchased the vehicle as a certified pre owned, I don't have a copy of the original sticker. I will have Toyota run the VIN to determine if I have original equipment or an after market. The alarm went off twice today, so far, once at 11:45 and again at 1:15. Yesterday, I tried opening the windows to see if a cooler interior would make a difference. The alarm went off about an hour later. The alarm has never triggered at night or when the car was parked in a garage. Again, thank for the input

 

Did you buy the car new?

Toyota states an alarm was standard but this may be the immobilizer system. There was supposed to be an optional glass breakage sensor optional but the part doesn't show up at a Toyota parts side for this year car. The sensor is a microphone.

Does the alarm have a Toyota FOB?

When the alarm goes of how do you reset it as in FOB, key in the door. ign switch?

 

The 2019 Camry was purchased in 2021 as Certified Pre-Owned. The car came with only one FOB which was issued by Toyota. The dealer ordered a second FOB for us that took a couple of months due to the chip shortage issue. The second FOB had to be programmed by a guy who, according my salesman, comes around every couple of weeks. Not sure if he works for Toyota. Both FOBs have the same functionality. The FOB shuts off the alarm by pressing the "unlock door" button. Interestingly, the alarm, will eventually shut itself off after about 45 seconds. This has happened twice when we didn't have the FOB handy. Another oddity occurred yesterday. The alarm went off and within seconds I turned it off using the FOB. However, I the relocked the car with the fob and the alarm immediately came back on.

 

Would assume a factory alarm.
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Did you try the window tap test?

 

Yes...tap test produced no reaction.

 

Read owners manual as it might state the alarm also responds to light. Any lighting issues?

FOB low battery or FOB switch issue? Something may be triggering the panic alarm.

A bad hood alarm switch.

 

The manual doesn't mention light as a problem source. The light I'm referring to is that from the sun and its warming effect. I believe the problem is being caused by heat buildup inside the vehicle passenger compartment or under the hood. As previously stated, the alarm stops tripping once the sun starts to go down behind our building and the vehicle is in shade. The FOB batteries are new and the vehicle battery checks out fine.

 

If your handy with electrical items try jumping the hood switch wiring to cut the switch out of the alarm loop.