P1143 2003 INFINITI G35 Possible Causes
- Faulty Heated Oxygen Sensor, Bank 1, Sensor 1
- Intake Air Leaks
- Open or Short Circuit in Bank 1, Sensor 1 Heated Oxygen Sensor Harness
- Poor Electrical Connection in Bank 1, Sensor 1 Heated Oxygen Sensor Circuit
- Fuel Pressure
- Fuel Injectors
How to Fix Code P1143 2003 INFINITI G35?
Start by checking the “Possible Causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.
Technical Notes
If there is no intake air leak, the most likely cause of the P1143 code is the Bank 1, Sensor 1 O2 sensor.
When is the Code Detected?
The maximum and minimum sensor voltages are not reached at the specified voltages.
Possible Symptoms
- Check Engine Light On (or Service Engine Soon Warning Light)
P1143 2003 INFINITI G35 Meaning
The Heated Oxygen Sensor 1 (Bank 1, Sensor 1) is located in the front pipe. It detects the amount of oxygen in the exhaust gases compared to the outside air. The Heated Oxygen Sensor 1 has a closed-end zirconia ceramic tube. The zirconia generates a voltage from about 1 V under richer conditions to 0 V under leaner conditions. The signal from Heated Oxygen Sensor 1 is sent to the Engine Control Module (ECM). The ECM adjusts the fuel injection pulse width to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the steep change from 1V to 0V.