The alarm system went off when I unlocked the door with the key and the car wouldn't start but the alarm system went off when i put the key in ignition but the car still wouldnt start

Disarming an Armed System/Silencing an Alarm
If system arming has been requested by the keyless entry transmitter, it must be disarmed.
Important: Using the power door unlock switch or manually unlocking the doors does not disable the CTD armed mode. Also, disconnecting the battery or pulling fuses does not disable the armed mode, since the BCM stores the CTD mode status in memory.
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To disarm the CTD system in arm pending mode, SECURITY indicator flashing and doors open, perform 1 of the following:

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Press the UNLOCK button on the keyless entry transmitter.

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Insert a valid key into the ignition and start the vehicle.

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To disarm the CTD system in the armed mode:

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Press the UNLOCK button on the keyless entry transmitter.

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Insert a valid key into the ignition and start the vehicle.

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To disarm the CTD system when activated, alarming mode.

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Press the UNLOCK button on the keyless entry transmitter.

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Insert a valid key into the ignition and start the vehicle.

I think that's the alarm system as well.the most important thing is the alarm system is still working?step out yr car try to use remote key to lock n unlocked,if that's working.i don't worry at all.lock n unlock are alarm system reset itself.should be normal,battery is super low or dead .good luck for u

are your batteries dead in all keys?

its the drivers door latch one of the switches change the latch

The alarm system somehow got activated , this is usually because the battery becomes discharged or disconnected try doing this:
Remove the key from the ignition
disconnect the negative battery terminal
put the key back in and turn to ON
exit the truck and leave door open
reconnect the battery terminal
get in and leave door open, if the alarm horn stays off it should start.

I have not a car but my father has a car and i knew that m father went to the car and was stayed yto there until alarm was stoped crying

you need to reset alarm/immobiliser.lock car with remote, hold button down for 30 secs,then press/hold down unlock button,should reset.another way is with key in ignition/turned on, press alarm button down and hold for 30 secs.this resets immobiliser.toyota
systems vary..depending on market.

With alarm activated your ignition is disabled.Find the combination to disable it.With GM's you hold opposing buttons on the fob till it beeps twice. The dealer should help for no charge.

When alarm goes off,put key in ignition and turn,the alarm should go off and alarm should be reset.Or,remove positive battery cable,wait 10 minutes,reconnect,when you open door,alarm will sound,insert key in ignition and turn key and alarm should go off and alarm should be reset.

OOPS dealer only ,Try opening and closing door lock three times drivers side 10 sec interval between clicks then try starting if no go then dealer only