I have a '09 Toyota Corolla & the SRS warning light is on. What is the problem & what do I need to do? Can it just be reset & would this repair be under warranty if it would need to be serviced?

you may have a failing or intermittent Toyota 4runner 2005 passenger occupant sensor for air bag Perhaps you need to take it to Toyota

https://resetservicelight.com/reset-srs-airbag-warning-light-toyota-4runner-fourth-generation/

When the SRS warning light comes on the system's control module has detected a fault, more than likely you have a fault code in the module you need read to see what is causing this, when the light is on the SRS is disabled. no airbags will deploy.

2000 Toyota Corolla, P0171 & P0420 codes - YouTube

? 5:43
https://www.youtube.com/watch?v=ahJnJ19-vwY
Jun 13, 2011 - Uploaded by StandardBrandParts
Standard Motor Products presents: Technician's Toolbox "2000Toyota Corolla, P0171 & P0420 codes"

Smoke testing for codes P0171 P0174 - YouTube

? 5:48
https://www.youtube.com/watch?v=kZsqEfP-5zM
Jan 18, 2011 - Uploaded by realfixesrealfast
These two codes mean a V style engine is running lean on both banks. So you have to be thinking - what can ...

How to repair fault code P0171 and reset warning light ...

? 26:31
https://www.youtube.com/watch?v=Y8FBGrCT3rM
Nov 27, 2014 - Uploaded by Peter Finn
How to repair and fix fault or error code P0171 and reset warning light Toyota Corolla VVT-i engine. ... Also how to find fault codeusing OBD scanner. ... Trouble shooting a misfire, Code P0300, P0301, P0302, P0303, P0304, P0305, P0306, ... 2000 Toyota Corolla, P0171 & P0420 codes - Duration: 5:43. by ...

I found this useful diagram at troubleshoot vehicle.com. It answers your question. Fuse box is located below steering column.
Driver Side Fuse Panel
(1993-1996 Toyota Corolla) December 21, 2013 Updated: December 21, 2013 Written by: Abraham Torres-Arredondo In the table below you'll find the fuse location and description of the fuses of the driver side under-dash fuse box on 1.6L and 1.8L 1993-1996 Toyota Corolla.
The fuse box is located on the driver side of the dash, below the steering column.
1993-1996 Toyota Corolla Driver Side Fuse Box Fuse Fuse Name Amps 1 Cigarette Lighter, Digital Clock, A/C System, A/T Shift Lock, Alarm, SRS Airbags 20 2 Tail, Parking & License Lights, Instrument Panel and Daytime Running Lights 15 3 Fuel Injection, Cooling Fans, Battery Discharge Light 10 4 Cruise Control System, Daytime Running Lights 10 5 Fuel Injection System 7.5 6 Stop Lights, Cruise Control, Shift Lock System, Anti-Lock Brake (ABS) System 15 7 Turn Signals, Emergency Flashers 10 8 Starting System, Anti-Lock Brake (ABS) System, Shift Lock System 15 9 Gauges, Reminder Lights, Back-up Lights, A/C System, Daytime Running Lights 10 10 Front and Rear Wiper/Washer System 20

Someone needs to access the body computer with a scanner to clear the code or codes and turn the light off.
You may be able to disconnect the battery for an hour or two and do it.

Try taking the efi relay out for about a min and than reinstalling,or just remove batteries out and reinstall.
Computer might need resetting by a Tech head with proper diagnostic tool

Remove the negative battery cable for about 25 seconds to see if it will reset,if it does not,then the air bag module is bad,Rate if this was at all helpful,thank you.

SRS SYSTEM HAS A FAULT , THIS COULD MEAN MANY THING
INPORANT TO KNOW SRS DOES A SELF CHECK EVERYTIME YOU START YOU VEHICLE , THIS LETS YOU KNOW IF THE SYSTEM IS WORKING OR NOT.

IT LOOKS AS IF YOU HAVE A FAULT WITH A PART OF THE SRS CIRCUIT.
PLEASE DO NOT TRY TO FIX , COULD BE DANGEROUS!!!
YOU NEED TO TAKE IT TO YOUR LOCAL DEALER.
THEY WILL SCAN SYSTEM.
AFTERMARKET GARAGES DONT HAVE AXCESS TO THE SRS SYSTEM.
THERE COULD BE A SHORT OR OPEN IN CIRCUIT.
I HOPE THIS HELPS

Check under the front seats , there should be electrical cables and connections, check they are ok, its possible something like a bottle can roll under the seat and catching the cable connector make bad contacts , putting on the warning lamp. If they appear to be ok and its still on, then go to the dealer to test the system.

There is a fault. Most common fault is due to the wires under the seats getting snagged by the rear carpet mats.
Check those wires, the car will need to be plugged into a code reader to expore & reset the SRS system