HO2S Bank 1 Sensor 1 Control Limit Reached
2011-2015 Kia Optima 2.4L I4
Description
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.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1166 on Other Vehicles
Common Questions
What does code P1166 mean on a 2011-2015 Kia Optima?
P1166 stands for "HO2S Bank 1 Sensor 1 Control Limit Reached". 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.
What are the symptoms of P1166 on a Kia Optima?
Common symptoms of P1166 include: Check Engine Light, Poor fuel economy, Rough idle, Hesitation, Failed emissions test.
What causes P1166 on a 2011-2015 Kia Optima?
Common causes of P1166 include: Large vacuum leak, Faulty upstream O2 sensor, Exhaust leak before sensor, Fuel pressure out of range, MAF sensor malfunction.