Persistent alarm sound not car alarm

[Shimatta]

Hey everyone. Got a 2005 4runner 6cyl. SR5 4wd. Haven't driven car in a week and today unlock with key fob (tried it with both fobs) and as soon as i turn ignition to accessory a loud warning like alarm goes off. Not the car alarm itself. Starts and drives fine except the persistent alarm like sound. Only light on dash is from TPMS which has been on for about a week. I have a 2 bad sensors and saving money to have them replaced. No aftermarket alarm or anything. anyone have any ideas?
thanks,
Jim

 

[ArthurKotb]

From bleeding my rear brakes a few weeks ago I know there's an alarm that goes off if the pump doesn't get enough pressure. I don't recall if there was a warning light or not. With the rear caliper bleed valve open, key in run position but not started, stepped on the brake and after about 10-15 seconds an alarm went off.

 

[AuSeeker]

Not sure without hearing what you're hearing, maybe do a video?

 

[Shimatta]

Thanks

Thanks for the replies. Checked the wheels and no wet spots and the brake fluid reservoir is within limits. In addition went out this am and no alarm any longer. I am going to take it to my mechanic and have him check out brake system just in case. Read some places that said it could be master cylinder or the brake booster is failing.
Thanks
Jim