My 2003 hyundai elantra's check engine light is on.

SOURCE: 2003 Hyundai Elantra - diable alarm

YES!... with various system operating difference. Disconnecting the alarm does not disable it.. it only silences the alarm. You will still need the Keyless Entry System Remote to RESET the alarm to start the vehicle.

Jeremiah Meyer

• 204 Answers
• Posted on Nov 19, 2008

SOURCE: PO420 code for 2003 Elantra

Danny,

Catalytic Converter Failure is a common cause of a P0420 Code. 1.) I would give a few calls to some muffler shops and get a thorough exhaust inspection done. As a leaking/damaged Exhaust Manifold, Catalytic Converter, or exhaust pipe could be some of the culprits as well. If it were any of those other items your car would give you a different OBD Code. Item #2.) This is not common with a P0420 Code. With the P0420 code you should have no driveability issues. (not to say that you wouldnt in an extreme rarety) Item #3.) Again this would flag an entirely different code such as P0455 (Large Evap Emission Leak) Item#4.) Engine Oil would not even set a code. I hope this helps you out, and thank you for using FixYa!

Sincerely,

JC

SOURCE: Adjusting the low beam headlight

its all the same the headlight is a complete unit you adjust both/ look for screws behind the headlight one each side one is for horizontal annd the other is for vertical Please rate my response thank you very much

SOURCE: P0139 code for a 2003 hyundai elantra. What is this code?

P0139 HO2S Circuit Slow Response (Bank 1 / Sensor 2). This is the downstream sensor (after the catalytic converter). Odds are the sensor is going bad. Check connections/ connector to this sensor. If you don't find any problem/trouble with this connector, replace the O2 sensor.

SOURCE: 2003 Hyundai Elantra GLS. Check engine light, code PO133

Did you use a aftermarket O2 sensor or a genuine Hyundai one? If it's an aftermarket one it may be bad or not as good as the OEM one. See here for more details and other potential causes: P0133