2002 Hyundai Accent 1.6 Check engine code

Probably replaced a good sensor. This codes could be from a bad sensor, a vacuum leak, or an exhaust leak before the sensor.

To find a small vacuum leak, let the engine idle, spray around the vac and induction area with carb cleaner or WD40 and listen for a change in the engine note/speed. This should narrow the search area. Good Luck

Have the fault codes read Replace the faulty units with genuine one because most aftermarket units are not set
for OEM cpu units and are not completely compatible

The 2000 model year Accent adopts a different "pressurized" leak check system capable of detecting a 0.020" (0.5 mm) diameter leak (previous Hyundai systems detect a 0.040" [1mm] diameter leak using engine vacuum). The new system uses a Diagnostic Module for Tank Leakage (DM-TL) to close and pressurize the fuel evaporative emissions system. The DM-TL replaces the fuel tank pressure sensor and the canister close valve from previous systems. Other significant changes were made to the system logic, including several new diagnostic trouble codes. It compares the differences between the 2000 model year Accent and previous evaporative emission systems... Que puede ser? Tiene dos opciones. Primero, puede pagar que un tecnico diaga el problema (exactamente) o sigue, secudariamente, su adivnaza.

You have a vacuum leak. This means that you will need to go through all of the vacuum likes and make sure they are connected and not broken. If they are broken buy new vacuum line, its like less and $1 per foot. In your case if you can I would replace all of the vacuum lines if they look cracked and old.

When you get any code,it does not tell you anything is wrong or what to replace

You use the code to diagnose the part of the system,that set the code

Most likely cause for an O2 Code, is a vacuum leak,which drives the sensor lean, and it goes out of range. Thus the code is set (Education is the Key )

You have at least two O2 sensors for every single exhaust,four or more for dual exhaust.

Your current code may be a new problem

Clean the IAC and check for vacuum leaks on all the vacuum hoses. Please rate me on this answer.

Fuel trim too lean. Usually means vacuum leak. Look for crushed,broken or melted off vacuum hoses near intake manifold. Or an obvious hissing noise at a normal idle. If so replace or repair clear codes your done. If not obvious take carb cleaner spray with nozzle attached car running & go over all vacuum hoses,intake manifold,egr valve see if idle raises if so you found leak. Repair. Could also be bad oxygen sensor switching bad o2 sensor but rarely.

Comment from the FixYa Moderator Staff:

I DISAGREE with the solution provided by Eliase.

You should NEVER spray 'starting fluid' in the engine compartment.

Starting fluid contains ether, and is extremely flammable.

Usage of staring fluid to look for vacuum leaks is a potentially dangerous situation.

I respectfully request that you refrain for using starting fluid.

What you CAN use, however, is a commonly found product, namely carburetor cleaner. This chemical is less flammable, and is used very often in the automotive business. Spray the carb cleaner near the intake manifold(s) where they connect to the block. If the idle changes, you have found the area that needs attention.

I would also doubt that you have a head gasket issue.

have a look at link below:
http://www.2carpros.com/first_things/check_engine_light.htm
Troubleshooting Procedure
1.Testing for DTS's (Diagnostic Trouble Codes)
2.Testing Fuel Pressure
3.Check Engine for Vacuum Leaks
4.Check for Plugged Exhaust System
5.Test for Weak Ignition Spark or Failing System
6.Check for Automatic Transmission Clutch Slippage