P1166
HO2S Bank 1 Sensor 1 Heater Circuit Fault
2016-2021 Honda Civic 2.0L I4
Low SeverityPowertrain
Description
The heater circuit in the upstream O2 sensor has a malfunction.
Symptoms
- CEL
- Poor cold-start economy
- Extended warm-up
- Increased emissions
Common Causes
- Failed heater element
- Blown fuse
- Open/short wiring
- Corroded connector
Diagnostic Steps
- Test heater resistance
- Check fuse
- Inspect wiring
- Test PCM relay
Repair Notes
Replace O2 sensor or repair heater circuit.
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 2016-2021 Honda Civic?
P1166 stands for "HO2S Bank 1 Sensor 1 Heater Circuit Fault". The heater circuit in the upstream O2 sensor has a malfunction.
What are the symptoms of P1166 on a Honda Civic?
Common symptoms of P1166 include: CEL, Poor cold-start economy, Extended warm-up, Increased emissions.
What causes P1166 on a 2016-2021 Honda Civic?
Common causes of P1166 include: Failed heater element, Blown fuse, Open/short wiring, Corroded connector.