2006 Hyundai sonata. I have an after market NX605 clarion head unit just stopped coming on. When I start the car the screen flashes "intelligent VOICE" then it just goes back to black screen with the word clarion. It does this repeatedly but never comes on. Does it need to be reset, is this something to do with antitheft system, I have tried a thousand different ways of getting in contact with clarion but so far nothing but very poor customer service and still no answers. Please if anyone knows what I need to do please help

SOURCE: my 2006 hyundai sonata alarm keeps going off

One word:

Dealer.

Next time just disconnect the battery until you get it towed as this is a warranty item. I'll bet some wondered if this was a prank question like I did, right?

SOURCE: antitheft and battery lite on 2006 ford freestar

Try your spare key first. also, does the anti theft visual indicator (red flashing light) prove out, that is light for three seconds when key is turned to on.

here's some info.

Principles of Operation
The passive anti-theft system (PATS) uses a specially encoded ignition key. Each encoded ignition key contains a permanently installed electronic device called a transponder. Each transponder contains a unique electronic identification code out of over 18 billion, billion combinations.
The passive anti-theft system (PATS), also known as SecuriLock ®, uses radio frequency identification technology to deter a drive-away theft. This system is known as SecuriLock® in North America, Safeguard® in the U.K., and PATS in continental Europe. Passive means that it does not require any activity from the user.
The SecuriLock® System (PATS) is not compatible with NON-FORD remote start systems, which allow the vehicle to be started from outside the vehicle. These systems may reduce the vehicle security level, and also may cause no-start issues. If equipped, the remote start system must be removed before investigation of PATS-related, no-start issues.
Each encoded ignition key must be programmed into the vehicle's powertrain control module (PCM) before it can be used to start the engine. The correct ignition key is a different design than prior model years. Consult the Rotunda Key Ordering Guide for the correct part number. There are special diagnostic repair procedures described in this section that must be carried out if a new encoded ignition key is necessary.
This system contains a new feature named Unlimited Key Mode. This feature allows a customer to program more than eight keys to the vehicle if they request it. Each vehicle in Unlimited Key Mode is set up with a special unlimited transponder security key. This allows all the customer vehicles to share the same keys, but no other keys from outside can be used to operate the vehicles. For an individual customer, any randomly selected security key is acceptable. Refer to Unlimited Key Mode Programming in Key Programming Switch State Control in this section.
The PATS transceiver module communicates with the encoded ignition key. The module is located behind the steering column shroud and contains an antenna connected to a small electronics module. During each vehicle start sequence, the transceiver module reads the encoded ignition key identification code and sends data to the PCM.
The control functions are contained in the PCM. This module carries out all of the PATS functions, such as receiving the identification code from the encoded ignition key and controlling the engine enable. The PCM initiates the key interrogation sequence when the vehicle ignition switch is turned to RUN or START.
All elements of the PATS must be functional before the engine is allowed to start. If any of the components are not working correctly, the vehicle will not start.
PATS uses a visual theft indicator. The indicator will prove out for three seconds when the ignition switch is turned to RUN or START under normal operation. If there is a PATS concern, this indicator will either flash rapidly or glow steadily when the ignition switch is turned to RUN or START. The PATS system also flashes the theft indicator every two seconds at ignition OFF to act as a visual deterrent.
PATS will be activated and will disable the vehicle from starting if there is:

• an incorrectly encoded ignition key.
• a damaged encoded ignition key.
• an unprogrammed key
• a non-encoded key (key has no electronics).
• damaged wiring.
• a damaged transceiver.
• a damaged PCM.

SOURCE: not ready codes

There is a long drive cycle for this issue and it is a tsb so it should be free. Have them call hyundai tech line to get the drive cycle. Its so long i could never type it out for you. Its pages but it works. If the dealer gives you any problems call hyundai consumer affairs and they will take care of it for you. the number is in your owners manual or ask a sales person. Hyundai cansumer affairs will do anything to make you happy. Hope this helps good luck.

SOURCE: Radio Reset for 2006 Hyundai Sonata

doubtful probably burnt up a component in radio thats why when jumping a vehicle u turn off all accessories so when something gets crossed it doesnt short it out usually will blow a couple of fuses

SOURCE: Hyundai Sonata 2006 - Check Engine light came on.

"Fuel system too lean at idle". It's an air/fuel ratio that is not correct, possibly a vacuum leak somewhere. Or a leaky exhaust pipe. Could be related to intake manifold gasket. Somewhere, air is getting into the engine.

I suggest taking it back to the dealer under warranty. I think Hyundai is 10yr./100k for the original owner. 5yr./50k if not. Ask first if covered, and ask why not id not covered.