P1148
Powertrain Codes
P1148 - INFINITI - Closed Loop Control Function Bank 1
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
Possible Causes
For Models 2005 and up:
- Air Fuel Ratio Sensor 1 Bank 1 circuit is open or shorted
- Air Fuel Ratio Sensor 1 Bank 1 circuit electrical connection
- Faulty Air Fuel Ratio Sensor 1 Bank 1
For Models before 2005:
- Heated Oxygen Sensor 1 Bank 1 circuit is open or shorted
- Heated Oxygen Sensor 1 Bank 1 circuit electrical connection
- Faulty Heated Oxygen Sensor 1 Bank 1
When Detected
The closed loop control function for bank 1 does not operate even when vehicle is driving in the specified condition, the closed loop control function for bank 2 does not operate even when
vehicle is driving in the specified condition.
Description
The Engine Control Module (ECM) performs ON/OFF duty control of the Air Fuel Ratio (A/F)/Heated Oxygen Sensor 1 heater corresponding to the engine operating condition to keep the temperature of Air Fuel Ratio (A/F)/Heated Oxygen Sensor 1 element at the specified range.