Codes P1166 and P1167?

P1156 check this link, http://engine-codes.com/p0156_hyundai.html P1167 check http://engine-codes.com/p1167_hyundai.html Both O2 sensor related codes. Hyundai as a car manufacturer put a lot of free technical information and workshop manuals on line for Hyundai owners. Check out www.hmaservice.com lots of great information.

Some commonly missed points- whatever code,sensor err codes usually are good sensors warning of the symptoms of a sick engine, not bad sensors. (Haynes publishes test procedure and includes 'pinout' information for heated O2 and other sensors; resistance of the heater element as well as operating(input & output) voltage parameters, operating temp etc; a digital VOM is needed for testng- unless inspection reveals dirty/soot clogged so no sample exhaust gets through it)WE ARE WARNED NOT TO USE ANY CLEANERS OR SOLVENTS ON THE SENSORS and to CAREFULLY apply special sensor-compatible(ELECTRICALLY CONDUCTIVE) anti-sieze upon (re)installation The sensor BEFORE (upstream) of the CAT sends data to compute timing adjusts & fuel injector "trim" regulating amount of fuel injected to cylndrs (with #1 usually the "test-point") After the CAT the downstream O2 (or "HO2S")sensor verifies proper regulation of fuel & timing parameters do permit "clean" exhaust to exit the catilytic converter. You can deduce then that nearly any "continuous-operating sensor" if faulty can cause the air/fuel ratio to fall outside of specified parameters where a good Heated Oxygen Sensor (HO2S) will return a fault code based on either "generic" (I think its SAE?) codes or 'non-existant' "factory-specific" codes such as P1166 (unique to Hyundai)which cant be found in most directories of fault codes packed with most code scanners Between the lines here you can see Ive given you a few 'heads-up' warnings to remember when troubleshooting and/or selecting tools for same... ...by now I hope the original poster solved their problem, but I wish good-luck to whomever is reading this and remind you all that the (limited) power of prayer has apparently been recognized by nearly every culture and 'tribe' of mankind even since before recorded history; your trouble should not be so elusive!