Vehicle locks by pressing button on door handle but trunk stays unlocked. Do I have to use the key fob to actually lock the vehicle?

google how to program fob for 2011 chevy malibu for more info

On the Chevy key fob, press and hold the "Unlock" and "Lock" buttons at the same time until you hear the door lock and unlock again. This means you're all set. Re-insert the programmed key back into the ignition to the "On" position to finish the Chevy key fob programming process

I'm assuming you are using a remote starting system from outside the vehicle? Can you actually get into the vehicle? Press the unlock button and try All the doors. This issue might be a faulty lock mechanism on one door so the other doors might unlock and the faulty one will stay locked. Replace the battery in the fob. A weak fob battery can also cause random issues with locking and starting and the batteries are usually cheap to buy. Next check the fuses for the Door Locks. The fuse will be in the engine bay fuse box. It will be labelled as either 'DOOR LOCK', (20A) or as 'B+', (40A). Try this website for a diagram of which fuse is where.

https://fuse-box.info/kia/kia-forte-cerato-2019-fuses-and-relays

LOCKING AND UNLOCKING
You can use the power door lock control or the remote control to lock and unlock your doors and tailgate.See Tailgate Lock.
Power Door Locks
The power door lock control is on the driver and front passenger door panels.

AUnlock.
BLock. Remote Control
You can use the remote control at any time your vehicle is not running.
Unlocking the Vehicle (Two-Stage Unlock)
Press the button to unlock the driver door. Press the button again within three seconds to unlock all doors.The direction indicators flash. The direction indicators flash twice to confirm the change. The unlocking mode applies to the remote control, keyless entry keypad and intelligent access.
Press and hold both the lock and unlock buttons on the remote control for four seconds to disable or enable two-stage unlocking. Disabling two-stage unlocking allows your entire vehicle to unlock with one press of the button.
Intelligent access at the driver door unlocks your entire vehicle when you disable two-stage unlocking.
Locking the Vehicle
Press the button to lock all doors.The direction indicators flash.
Press the button again within three seconds to confirm that all the doors are closed.The doors lock again, the horn sounds and the direction indicators flash if all the doors are closed.
Mislock
If any door is open, or if the hood is open on vehicles with an anti-theft alarm or remote start, the horn sounds twice and the direction indicators do not flash.
Activating Intelligent Access
General Information
You can unlock and lock the vehicle without taking the keys out of your pocket or purse when your intelligent access key is within 3 ft (1 m) of your vehicle. Intelligent access uses a sensor on the back of the door handle for unlocking and a separate sensor on the face of each door handle for locking.
The system does not function if:

• Your vehicle battery has no charge.
• The key battery has no charge.
• The key frequencies are jammed.

Note: The system may not function if the key is close to metal objects or electronic devices, for example keys or a cell phone.
Note: If the system does not function, use the key blade to lock and unlock your vehicle. See Remote Control.
Unlocking Using Intelligent Access
With your intelligent access key within 3 ft (1 m) of your vehicle, touch the unlock sensor on the back of the door handle for a brief period and then pull on the door handle to unlock, being careful to not touch the lock sensor at the same time or pulling the door handle too quickly. The intelligent access system requires a brief delay to authenticate your intelligent access key fob.
Locking Using Intelligent Access
With your intelligent access key within 3 ft (1 m) of your vehicle, touch the outer door handle lock sensor for approximately one second to lock, being careful to not touch the unlock sensor on the back of the door handle at the same time. After locking, you can immediately pull on the door handle to confirm locking occurred without inadvertently unlocking.
Note: Do not use the outside door handle as a roof cargo strap.
At the Electronic Tailgate (If Equipped)
Press the exterior tailgate release button inside of the tailgate handle. The tailgate unlocks and opens. See Electronic Tailgate.
Smart Unlock
This feature helps to prevent you from locking your intelligent access key inside your vehicle's passenger compartment or rear cargo area.
If you leave your key in the ignition, when you open the driver door and lock your vehicle with the power door lock control, the doors lock then unlock.
You can still lock your vehicle with the key in the ignition by:

• Using the manual lock on the inside of the door.
• Locking the driver door with a key.
• Using the keyless entry keypad.
• Using the lock button on the remote control.

Smart Unlocks for Intelligent Access Keys
This feature helps to prevent you from locking your intelligent access key inside your vehicle's passenger compartment or rear cargo area.
When you lock your vehicle using the power door lock control (with the door open, vehicle in park and ignition off), your vehicle searches for an intelligent access key in the passenger compartment after you close the door. If your vehicle finds a key, all of the doors immediately unlock.
In order to override the smart unlock feature and intentionally lock the intelligent access key inside your vehicle, you can lock your vehicle after all doors are closed by using the keyless entry keypad, pressing the lock button on another intelligent access key or touching the locking area on the handle with another intelligent access key in your hand.
When you open one of the front doors and lock your vehicle using the power door lock control, all doors lock then unlock if the ignition is on.
Autolock
Autolock locks all the doors when:

• All doors are closed.
• The ignition is on.
• You shift into any gear putting your vehicle in motion.
• Your vehicle reaches a speed greater than 12 mph (20 km/h).

Autolock repeats when:

• You open then close any door while the ignition is on and your vehicle speed is 9 mph (15 km/h) or lower.
• Your vehicle reaches a speed greater than 12 mph (20 km/h).

Autounlock
Autounlock unlocks all the doors when:

• The ignition is on, all the doors are closed, and your vehicle has been moving at a speed greater than 12 mph (20 km/h).
• Your vehicle comes to a stop and you switch the ignition off or to the accessory position.
• You open the driver door within 10 minutes of switching the ignition off or to accessory.

Note: The doors do not autounlock if you electronically lock your vehicle after you switch the ignition off and before you open the driver door.
Enabling or Disabling Autounlock
You can enable or disable the autounlock feature in the information display or an authorized dealer can do it for you. See General Information.
Illuminated Entry
The interior lamps and select exterior lamps illuminate when you unlock the doors with the remote entry system.
The illuminated entry system turns off the lights if:

• The ignition is on.
• You press the remote control lock button.
• After 25 seconds of illumination.

The dome lamp does not turn on if the control is set to the off position.
The lights do not turn off if:

• You switch them on with the dimmer control.
• Any door is open.

Battery Saver
The battery saver turns off the interior lamps 30 minutes after you switch off the ignition if a door is open and the dome lamp switch is on. It turns off the interior lamps after 10 minutes if the dome lamp switch is off.
Accessory Mode Battery Saver for Intelligent Access Keys (If Equipped)
If you leave the ignition on after leaving your vehicle, it turns off 15 minutes after you close all of the doors.

How are you trying to open the door , button on key fob ? With this system you can pull up on the drivers handle an it activates Antennas in the external side door handles (C30/C70 front doors, S40/V50 rear doors)

Antennas in the passenger compartment and cargo compartment

An antenna in the rear bumper

Quick lock motors in the lock units in the side doors

The remote keyless entry (RKE) receiver receives a signal from the key

The switch in the clutch pedal (manual transmissions) or a signal from the brake pedal switch via the central electronic module (CEM) (automatic transmissions)

Key-in switch.

Switch in door handle and lock button on handle .
If a door handle is pulled outward, a switch closes that wakes up the system and activates the antennas in the handles on the side where the handle has been pulled out. If a valid key is within a radius of approx. 1.5 metres from the handle, the relevant door will open and the vehicle will unlock one or several doors. Which doors are unlocked depends on the settings for the system. The vehicle can also be unlocked if the handle is affected on the tailgate.

Sounds like the remote receiver module in the car is malfunctioning and will probably need to be replaced.

When you press the trunk open button, do you hear any "release" noise come from the trunk area? The issue may be a bad battery in the key fob OR there could be an issue with the transmitter located inside the vehicle. Do the doors lock and unlock properly? is the vehicle equipped with security or immobilizer? please advise

If your key fob has just stopped working try this:

1. Unlock your vehicle with the key in the drivers door lock, do not open the door.
2. Press the right hand button lock button (the button with the padlock symbol or the dimpled button) on the key fob 4 to 8 times.

If the above fails try this:

1. Open the key fob
2. Remove the battery
3. Press any button 10 ten times, and the same with the other button
4. Refit the battery or a new battery
5. Unlock the vehicle with the key in the drivers door lock, do not open the door
6. Press the right hand button lock button (the button with the padlock symbol or the dimpled button) on the key fob 4 to 8 times

Retrain the fobs following the procedure in your owner's manual:


Once entering this procedure, programming the first transmitter erases all previous transmitters. You must program all transmitters.

Program one vehicle at a time. One transmitter could be programmed into other vehicles that are also on
program mode in close proximity.
1. Sit in the driver's seat.
2. Remove the ignition key from the ignition lock cylinder.
3. Close all vehicle doors.
4. Press and hold unlock on the door lock switch.
5. While holding the door lock switch in the unlock position, insert and remove the ignition key twice. Do
not rotate the ignition lock cylinder.
6. Insert the ignition key a third time leaving the key in the ignition lock cylinder. The ignition must remain
in the LOCK position for the rest of the procedure.
7. Release the door lock switch. You will hear three chimes. This chime feedback indicates that transmitter
programming is active.
8. Press and hold the lock and unlock buttons at the same time on the keyless entry transmitter for 12
seconds. You will hear two chimes. This chime feedback indicates that the transmitter has been
programmed successfully.
9. Repeat step 8 for the rest of the transmitters (for a total of 4 transmitters).
10. Exit this procedure by removing the ignition key from the ignition lock cylinder.

Programming
When
Key added or replaced. System malfunction.
How
Obtain all keys. A maximum of 3 keys can be programmed. Close all doors and boot/tailgate. Switch ignition ON. Repeat procedure below 3 times: Within 4 seconds: Press key lock or unlock button. Within 4 seconds: Switch ignition OFF. Within 4 seconds: Switch ignition ON. Within 4 seconds: Press key lock or unlock button. System should now lock or unlock vehicle. Within 4 seconds: Press key lock or unlock button. Within 10 seconds: Press lock or unlock button of first key. System should now lock or unlock vehicle. Press lock or unlock button of second key. System should now lock or unlock vehicle. Press lock or unlock button of third key. System should now lock or unlock vehicle. Switch ignition OFF. Remove key. Check operation of all programmed keys.
NOTE: If less than 3 keys are to be programmed, remove ignition key after programming last key.

You should not have to reset the key fob after a battery replacement. The signal from the key fob stays the same and is programed to the reciever.
If the key fob needs to be reprogrammed then follow these steps.
1. Have all key fobs with you during programming.
2. Sit in the vehicle with all doors closed.
3. Lock all doors using the Lock/Unlock switch on the door.
4. Insert and withdraw the ignition key 7 to 9 times within 10 seconds (do not turn the key, just insert and withdraw).
5. The 4 way flasher indicator on the dash should flash once or twice.
6. Insert the ignition key and turn it on (key on, engine off).
7. Press any button on one remote and the 4 way flasher indicator on the dash should flash once.
8. If you have more key fobs to program use the Lock/Unlock button on the door to unlock the doors and then lock the doors.
9. Press any button on the next key fob and the 4 way flasher indicator on the dash should flash once.
10. Repeat if you have more key fobs. Only 5 can be programmed.
11. To exit, simply turn of the igniton and remove the ignition key.
12. Unlock the doors using the Lock/Unlock switch on the door and exit the vehicle.
13. Make sure the window is down when testing remotes in case you leave the keys inside.
14. Close all doors and test all remotes that were programmed.

Do not skip any steps or the process will not work.

If the 4 way flasher indicator does not work when inserting the key, you will need to start the process from the begining. If it still does not work the receiver may be your problem.

If the 4 way flasher indicator does not flash when pressing any button on the key fob then the key fob is the problem (dead battery or defective remote)