P1166moderate severityPowertrain
HO2S Bank 1 Sensor 1 Control Limit Reached
on 2006 Kia Optima 2.4L I4 · FWD
What this code means
The PCM has detected that the fuel control correction based on the Bank 1 upstream O2 sensor has reached its maximum limit. The PCM can no longer adequately compensate for the air-fuel ratio deviation.
Symptoms
- Check Engine Light
- Poor fuel economy
- Rough idle
- Hesitation
- Failed emissions test
Common causes
- Large vacuum leak
- Faulty upstream O2 sensor
- Exhaust leak before sensor
- Fuel pressure out of range
- MAF sensor malfunction
Diagnostic steps
- Check fuel trim values on scan tool for direction of correction
- Test for vacuum leaks
- Monitor O2 sensor switching
- Check fuel pressure
- Inspect MAF sensor
Repair notes
Repair the underlying air-fuel ratio issue causing the control limit to be reached.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1