Car alarm/remote starter won't work. The 2 way keyless works, but the one way with new cr2025 batteries doesn't.

My remote key won work

When Your Keyless Entry Doesn Work Enlighten Me

ITS A BUTTON USUALLY UNDER THE DASH

Is this an issue with all 2008 HHR remotes??? Highly doubtful , probably the vehicles keyless entry system . Taking the vehicle to a qualified repair shop an having the keyless entry system checked for DTC'S - diagnostic trouble code's . Do you know what a DTC is ?
The keyless entry system is a vehicle entry device. The keyless entry system is used in conjunction with the body control module (BCM) to remotely activate certain vehicle features. Keyless entry will lock/unlock the doors, or release the rear compartment lid when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the transmitter sending a radio frequency to the remote control door lock receiver (RCDLR). The RCDLR interprets the signal and activates the requested function via a serial data message to the BCM. A low transmitter or vehicle battery or radio frequency (RF) interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High RF traffic areas may also cause interference that could lead to a malfunction. Keyless entry allows you to operate the following components:
• Door locks
• Liftgate lock
• Remote rear doors (Panel only)
• Vehicle locator/panic alarm
• Illuminated entry lamps
• Remote vehicle start
The keyless entry system has the following components:
• Keyless entry transmitters
• Keyless entry antenna
• 2 Way Advanced Remote Start RCDLR
• BCM

Guessing will not fix this .

Does the spare remote work? Have you tried to reprogram it? These remotes are very cheaply made and prone to key pad failure. To program the remote click this LINK, if that doesn't work buy anew one on eBay for cheap.

best thing to do would to take it to either the dealer or a car audio place that deals with alarms

The 2003 Sonata is equipped with a 'starter KILL' burglar alarm system with disables the starting system (using a N/C 'contacts' configuration instead of a N/O contacts configuration). N/C=Normally closed, and N/O=Normally open contacts. When the alarm goes off with a MY Sonata, the only way to DISARM it is with the key fob (remote) originally programmed for it (unless you purchase a new remote & have it programmed for the vehicle at an authorized Hyundai Service Department). NOTE: So long as the keyless entry & burglar alarm system is functioning/operating normally, the alarm will keep going off and the STARTER KILL function will still prevent you from starting the vehicle. One option is left without purchasing a new remote and having it programmed.
1. When the alarm goes off, get into the vehicle and insert the ignition key into the ignition.
2. Turn the key to the 'RUN' position (NOT the ACC position) and wait for the alarm to STOP (usually about 3 to 5 minutes).
3. The engine should then start using the ignition key.

If this procedure doesn't work, the problem will need further diagnosis by a qualified/certified Hyundai Service Technician.

Hope this helps

before you spend too much money...try this.
On the inside of the keyless remotes, there are rubber buttons, those rubbers buttons are brushed with metal of some sort so that it reacts with the motherboard, when the remotes get older this metal wears off...so try this, it worked for me...
I superglued foil paper to the back of the button (the parts that touches the motherboard when pressed) and replaced the batteries... it worked like a charm, I used an awl and a hammer to make perfectly round piece of foil and just glued it onto the back of the button... i'd try this first before spending any real money.

replace remote battery to make sure, but if alarm is activated it continous to chirp the alarm or if your alarm system is set by the manufacturer try to relearn the program, if all fuse are ok, and your remote lock/unlock is work, check for lose ground connection, if remote is not working, replace the battery then try to do this. swtch ignition in 10 seconds to on-off-on-off-on-off-on-off-on wait 30 seconds, press any button of the remote once, turn igniton off, after 30 seconds start the car, if not go to the nearest service center to check the troublecodes

That's not a remote starter on your key chain, it's a keyless entry for an alarm system.